In consideration of the light weight and the impact safety of cars, in recent years, hot stamping has been increasingly applied to the manufacture of car parts, which has driven forward the increasing use of ultra-high strength steel sheet in the automobile industry. However, when the tensile strength of steel is more than about 1200 MPa, the steel sheet is very susceptible to hydrogen induced delayed fracture. Up to now, some research has been carried out on delayed fracture behavior of both high strength and ultra-high strength steel sheet. However, the delayed fracture behavior of a low-carbon Mn-B type steel sheet widely used for hot stamping has not been paid enough attention and fully studied. There are also a scarcity of reports on hydrogen induced delayed fracture behavior of this steel sheet after hot stamping. With the development of the hot stamping, the evaluation of delayed fracture behavior of ultra-high strength steel sheet for hot stamping, especially the delayed fracture behavior of steel sheet after hot stamping has become very urgent. For these reasons, hydrogen induced delayed fracture behavior of a low-carbon Mn-B type ultra-high strength hot stamping steel sheet at both the hot stamped status and the common quenched and tempered status was studied by means of constant load delayed fracture test and hydrogen thermal desorption spectrometry (TDS) analysis. The results show that both the critical delayed fracture stress σ_c and delayed fracture life of the steel sheet after hot stamping process are higher than as-quenched sample, and it even matches the level of the quenched +100℃ tempered sample. Moreover, the σ_c of the steel sheet could be further improved by tempering at 200℃. The delayed fracture surface observed by SEM shows that, under the effect of applied stress and corrosive liquid, the fracture characteristic of the hot stamped sample at crack initiation area changes from brittle intergranular failure in the as-quenched condition to ductile transgranular failure in the hot stamped condition. Furthermore, the TDS result shows that the hydrogen content of steel sheet significantly increases when the steel sheet was applied at critical stress for 100 h in the corrosive liquid. In addition, the hot stamping steel sheet can withstand more hydrogen content than as-quenched sample and quenched +100℃ tempered sample due to the sufficient self tempering. As a result, the hot stamping sample gets a higher critical delayed fracture stress. Therefore, the steel has good delayed fracture resistance after hot stamping, and the delayed fracture resistance of the steel sheet could be further improved by tempering.

Enamel product has been developed and more widely used with the development of metallurgical technology and equipments. Its quality is closely related to its metal substrate which needs both nice mechanical properties to meet deep-drawing request and excellent hydrogen trapping ability to meet sufficient fish-scale resistance. In order to obtain those properties, the influence of continuous annealing process on microstructural characteristics, mechanical properties and hydrogen permeation behavior of boron containing enamel steel was investigated. The material was producedand processed in lab and the continuous annealing process was performed using a continuous annealing simulator. It was found that in annealed sheet using high temperature and short time soaking, the sizes of both ferrite grains and cemetite particles within matrix are relatively larger, pearlite exist independently; while using relatively low temperature and long time soaking, the size of ferrite grains is smaller, cemetite particles within matrix are fine and dispersed, pearlite exist as chains. Within the scope of the annealing process adopted, strengths and work hardening exponent n-values of annealed sheets do not differ much, elongations and plastic anisotropy ratio r-values are both high. High temperature and short time soaking is more advantageous to steel sheet obtaining strong γ-fiber texture, which benefits the deep-drawing of sheet. There are certain scale of MnS inclusions,pearlite and cementite particles, whose interfaces between matrixes can be used as effective hydrogen traps, so the hydrogen diffusion coefficient in steel is quite low. Relatively fine ferrite grains+degenerated pearlite chains and fine dispersive cementite particles in steel sheet annealed using relatively low temperature and long time soaking is more beneficial to reducing hydrogen diffusion rate,improving the fish-scale resistance of enamel steel.

The effects of annealing time on microstructure and mechanical properties of low silicon TRIP steel containing phosphorus and vanadium for hot-dip galvanization under ultra rapid heating were investigated. The results show that a high density of dislocations and the vanadium precipitate existe within matrix during ultra rapid continuous annealing, and most of the precipitated particle sizes are in the range from 4 to 10 nm. The volume fraction of retained austenite is increased with increasing annealed time, but the retained austenitic morphology is changed. The interlath retained austenite films with a thickness of 80－120 nm are　dominated with increasing annealed time to 90 s; the thickness of interlath　retained austenite films is increased to 200－600 nm and tended to block　structure continuing to increase the annealed time to 180 s. The yield and　tensile strength are decreased with increasing annealed time during ultra　rapid continuous annealing, however, the elongation and work harding index　are increased; the product of strength and ductility (R_m·δ) is decreased from   23976 MPa·% when annealed time is 10 s to 23625 MPa·% when annealed time is 180 s.

The austenitic stainless steels are widely used as structural materials of the workpieces served in severe environments, while the interfacial cracking in brazing joints of the austenitic stainless steels is a drawback limiting their application. Thus far the reports have not comprehensively revealed the formation mechanisms of the brazing cracks. To help solving this problem, formation mechanisms of the interfacial cracks at the 316LN stainless steel/filler metal brazing joints were comprehensively investigated in this study. The 316LN cooling pipes were firstly arc brazed with Cu-Si and Ag-Cu-Sn filler metals. According to the leakage test results of these pipes, microstructures of the brazing joints and the interfacial cracks were observed by OM and SEM, and compositions around the cracks were analyzed by EDS. The results show that the interfacial cracks initiate at the 316LN/filler metals interface and propagate along the grain boundaries of the stainless steel, elements of the filler metals were detected in the cracks, and it is confirmed that the cracks formed before solidification of the filler metals. To further reveal the crack formation mechanisms, verification tests including dipping (1100℃, 30 s) and vacuum-brazing (1100℃, 10 min) of 316LN with Cu-Si filler metal, arc brazing of 316LN with Ag-Al, Ag-Sn and Ni filler metals were conducted. The cracking was not observed at the vacuum-brazed 316LN/Cu-Si joint interface and the arc-brazed 316LN/Ni interface, but the other three brazing joints show similar cracking behaviors with the 316LN/Cu-Si joint. Base on the results, it was predicated that weakening of the grain boundaries in the 316LN induced by GB diffusion of the low melting point elements, and the brazing stress result from the temperature gradient in the 316LN substrate material during the brazing process are necessary formation conditions of the brazing cracks. Cracking at the brazing joint interface are affected by composition of filler metals, heating rate, thermal input, and heat treatment conditions of substrate materials. Brazing techniques were optimized according to the findings, and it was found that occurrence of the cracks can be restrained through decreasing the temperature gradient or avoid to used the low melting point elements-contained filler metals.

The metallic matrix composite with ceramic nano-particles has a wide prospect in many applications due to its superior properties. The nanocomposite Ni-WC coating has been synthesized by using DC co-electrodeposition of Ni with WC nano-particles. Its hardness was measured by using ultra-micro hardness tester. Its corrosion and passive properties were investigated in 0.05 mol/L H₃BO₃+0.075 mol/L Na₂B₄O₇ buffer solution with pH=9.0 by using potentiodynamic polarization measurement. As compared to pure nanocrystalline (nc) Ni, nanocomposite refined remarkably, with average grain size about 21 nm and the hardness increase of 80%, reaching about 651 HV. The corrosion current density i_corr is 1.29×10^-7 A/cm²,approximately one magnitude order lower than that of nc Ni. With the similar passive film breakdown potential, nanocomposite exhibits a lower passivation potential E_p of 10 mV and a much lower passive current density i_p of1.79×10^-6 A/cm², about 1/7 that for nc Ni. According to the Mott-Schottky analysis together with point defect model, the passive film on the nanocomposite exhibits p-type semi-conducting behavior,similar to that on the nc Ni. The grain refinement of Ni is beneficial to the reduction of both the donor density and diffusion coefficient.

The Zr-based metallic glass composite containing four kinds of W fibers with different diameters are prepared by infiltration casting method. The diameters of the W fibers are 1000, 700, 500 and 200μm,respectively. The effect of fiber diameter on the quasi-static and dynamic compressive mechanical properties and deformation behaviors of the composites was investigated. The results show that the quasi-static compressive properties improve with the decrease of the W fiber diameters, which is attributed to the increasing interface area and the size effect of the metallic glass matrix. Under dynamic compressive loading, the strain rate changes with the variation of the W fiber diameter at the same bullet firing pressure. The dynamic compressive strength and strain rate sensitivity exponent of the metallic glass composite with a fiber diameter of 500μm is the highest among the four W fiber/Zr-based metallic glass composites.

The Si particles with average size of 2μm were dispersed in plating solution, and the electrodeposition process of Fe-Si composite coating under a static magnetic field was studied. The influences of orientation, flux density of magnetic field (MFD) and current density on the morphology and Si content of Fe-Si composite coatings were discussed. It was found that the Si content of coatings for vertical electrodes increased significantly with increasing the MFD in both parallel and perpendicular magnetic field (regard to current) with the MFD ranging from 0 T to 1 T. In the case of aclinic electrodes, the Si content of coating can reach 37.94% (mass fraction) without magnetic field. However,after applying a perpendicular magnetic field, the Si content of coatings decreased sharply with increasing the MFD (only 2.83% at 1 T). Meanwhile,many striated iron matrix protuberances with Si particles appeared perpendicular to the direction of magnetic field on the coatings surface. Moreover, the Si content of coatings decreased with increasing current density for both aclinic and vertical electrodes in 1 T perpendicular magnetic field, while that for vertical electrodes first increased and then decreased and reached maximum value at about 20 mA/cm² in 1 T parallel magnetic field. Theoretical analysis shows that the change of morphology and Si content of coatings were mainly attributed to the formations of macroscopic magnetohydrodynamics (MHD) and micro-zone MHD effect caused by Lorenz force.

The corrosion in deep ocean environment has been paied more and more attentions to the exploitation of marine resources. Different from shallow marine environments, deep ocean environments are specially characterized by high hydrostatic pressure, low temperature, variable dissolved oxygen content and pH value in deep ocean, etc.. So the corrosion behaviour of materials, such as ferrous and nonferrous metal and coatings, in deep ocean environments is different from that in shallow marine environments. A number of researches have been carried out to investigate the corrosion behaviour of metals in natural deep ocean in a few developed countries. Such researches, however, began until 2008 in South China Sea. In this work, the corrosion behavior of H62 brass, QAl9-2 and QSn6.5-0.1 bronze in 800 and 1200 m deep ocean environments of South China Sea was studied using field tests. The results indicated that the corrosion rates of copper alloys decreased in the following order: H62 (0.042 mm/a) > QSn6.5-0.1 (0.004-0.007 mm/a) > QAl9-2 (0.003 mm/a). The corrosion rate of H62 brass decreased linearly with the increase in depth. While the corrosion rates of QAl9-2 and QSn6.5-0.1 bronze decreased first and then increased with the increase in depth. The minimum value of corrosion rate occurred between 800-1200 m. The morphology and composition of corrosion products were investigated using SEM, EDS and XRD. The results demonstrated that the dezincification corrosion obeying solution-redeposition mechanism in H62 brass occurred. The corrosion products were composed of Cu, ZnO, Zn₅(OH)₈Cl₂H₂O and Cu(OH)₂H₂O. And the dealloying corrosion in QAl9-2 and QSn6.5-0.1 bronze occurred. The corrosion products of QAl9-2 bronze consist of Cu₂O and CuCl₂, and those of QSn6.5-0.1 bronze Cu₂O, CuCl₂ and Cu₂Cl(OH)₃.

Aluminum alloys have been found ever-increasing applications in marine environments. The study on the corrosion of aliminum alloys using field test was started in USA in 1940s.Such studies, however, were carried out in China untill 1980s. Although the corrosion  behaviours of 11 kinds of aluminum alloys were investigated exposed to tide, splash and full immersion zones at Qingdao, Zhoushan, Yulin and Xiamen area of China, the corrosion behaviour of materials in deep ocean environments is different from that in shallow marine environments. In this work, the corrosion behavior of 5052 and 6061 aluminum alloys in 800 and 1200 m deep ocean environments of South China Sea was studied using field test. The morphology and composition of corrosion products were investigated using SEM, EDS and XRD. The results indicated that severe local corrosion took place in the aluminum alloys. The corrosion products were composed of Al₂O₃, SiO₂ and a small amount of Mg₃(SO₄)₂(OH)₂ and NaCl.The crevice corrosion perforation occurred on the edge of 5052 and 6061 samples.And the groove corrosion pits formed on the cross section of 5052 sample.Pitting corrosion took place on the main area of 5052 and 6061 samples.The size and density of pits formed on 6061 aluminum alloy were higher than those on 5052 aluminum alloy.And the pitting corrosion perforation formed on 6061 aluminum alloy in 800 m deep ocean.Comparing with the data of literatures,the maximum pit depths of 5052 and 6061 aluminum alloys decreased first and then increased with depth increased. The maximum value of pit depth appeared at about 800 m deep ocean. This is due to the amount of dissolved oxygen is the lowest in 800 m deep ocean, which promotes local corrosion.

Electronic structure and elastic properties of Mg₂Sn, Mg₂Ca and MgZn₂ phases were investigated by means of first-principles calculations from CASTEP program based on density functional theory (DFT). The calculated lattice parameters were in good agreement with the experimental and literature values. The calculated heats of formation and cohesive energies show that Mg₂Sn has the strongest alloying ability and structural stability. The density of states (DOS) of Mg₂Sn, Mg₂Ca and MgZn₂ phases were calculated to analyze the mechanism of structural stability and mechanical properties. The calculated band structures show that Mg₂Sn phase has the widest bandgap. The electron density difference indicate that bonding characteristics of Mg₂Sn, Mg₂Ca and MgZn₂ phases were all covalent bond, ionic bond and metallic bond. The elastic constants of Mg₂Sn, Mg₂Ca and MgZn₂ phases are calculated, the bulk moduli, shear moduli, Young's moduli and Poisson's ratio are then derived. Bulk moduli is assumed to be the ability of material resistance to volume change by applied stress, the larger bulk modulus of MgZn₂ phase shows that it has stronger ability to resist deformation. Shear moduli is a measure of resistance to shear strain deformation under the deformation condition of shear stress, the larger shear moduli value of Mg₂Sn phase indicates that it has the stronger ability to resist shear strain deformation. The calculated Poisson's ration shows that MgZn₂ has the largest value, and then followed by Mg₂Ca and Mg₂Sn. Hence, the plasticity of MgZn₂ phase is the best. The calculated Young's moduli of Mg₂Sn phase has the largest value and MgZn₂ phase has the smallest value. Hence, among the three phases Mg₂Sn phase has the strongest stiffness. The ratio of the shear moduli to bulk moduli of phase can be used to demonstrate the brittle and ductile of materials. The critical value, which separates ductility from brittleness, is about 0.57. A higher G/B_u value is associated withbrittleness, otherwise is ductility. The calculated values of Mg₂Sn, Mg₂Ca and MgZn₂ phases are 0.66, 0.53 and 0.18, respectively. The results show that Mg₂Sn is brittle, Mg₂Ca and MgZn₂ are both ductile.

The dendrite tip growth kinetic coefficients and Gauss distribution parameters for 3D－CAFE simulation are determined according to the main compositions of 430 ferrite stainless steel and the macrostructure forming under the experimental condition of slow cooling. Based on the repeated computation with different heat transfer coefficients, the heat transfer coefficient under slow condition is determined when the solidification structure by above simulation computation is basically the same as the experimental one under slow cooling. The temperature fields and flow fields of 430 ferrite stainless steel during the solidification process under the conditions of slow cooling, air cooling and water cooling were analyzed by use of 3D－CAFE method, respectively. The results show that the temperature field of solidification process under slow cooling condition is the most uniform and the solid－liquid region is the widest, followed by air cooling condition, while the temperature field under water cooling is quite non－uniform and the solid－liquid region is the narrowest. The maximum solidification rates are 2.3 mm/s with slow cooling, 3.0 mm/s with air cooling and 3.3 mm/s with water cooling, respectively, which are obtained in the center of the castings. The maximum flow rate is obtained in the center of casting with the value of 8.9 mm/s under slow cooling condition, and the maximum flow rate is 9.8 mm/s near the side wall under air cooling condition, while the maximum flow rate is 4.6 mm/s at the position with the 3/5 distance from the side wall under water cooling condition. The solidification structure of casting is composed of almost all equiaxed grains under slow cooling condition, and only a few equiaxed grains exist in the centre of casting under air cooling condition, while the solidification structure of casting consists of coarse columnar grains under water cooling condition.

The temperature dependence of Portevin-Le Chatelier (PLC) effect in a nickel base superalloy was investigated. A series of tensile tests were conducted ranging from room temperature to 900℃ at a constant rate 5×10^-4 s^-1. The critical strain,amplitude of stress drop, waiting time and flying time of serrated flow were analyzed in order to reveal the temperature dependence of PLC effect and its related micro-mechanism. The results showed that the normal behavior occurs as temperature changes from room temperature to 450℃, in which the critical strain of serrated flow decreases with increasing temperature while magnitude of the stress drop increases. The normal PLC effect is mainly controlled by pinning effect of solute atoms and its diffusion process. When temperature increases from 450℃ to 600℃, the critical strain of PLC effect increases and the inverse PLC effect appears. Since some dislocations are pinned by solute atoms prior to breakaway, the dominant factor of inverse PLC effect is that pinned dislocations get rid of solute atoms and move freely. With temperature increasing above 600℃, PLC effects disappear because it is difficult to form effective solute atmosphere necessary to lock mobile dislocations.

The previous particle boundaries (PPB) introduced in the PM (powder metallurgy) superalloys during their fabrication process are deleterious to the mechanical properties of the superalloys. The elimination and the minimization of the PPB are the keys to promote the metallurgical quality of the PM superalloys. The carbon replica methods and advanced analytic techniques were utilized to study the PPB formed in FGH96 alloy. The result shows that the multi--element carbides and largeγ′ phase decorate the outline of the PPB. The PPB precipitates in the alloy which is hot isostatic pressed (HIPed) below the solution temperature of theγ′phase are mainlyγ′ phase and MC (the metalic elements are mainly Ti,Nb and Zr), while those in the alloy HIPed above the temperature are MC.The supersaterated solutes on the powder surface react with the carbon andoxygen of the surface during the HIP process, which leads to theformation of the PPB precipitates. Besides, the segregation of the MC andγ′ phase forming elements speed up the reaction above. The characteristics and the elements segregation of the initial powder surface inevitably lead to the formation of PPB and, as a result, the PPB can not be completely eliminated. Selecting proper size range of the initial powders for HIP and strict controls of the HIP parameters are the key tominimizing the PPB.

Recently, there has been increasing interest in the transformation process between 18R and 14H long period stacking ordered (LPSO) structures in Mg-Y-Zn alloys. However, the detailed phase transformation associated with 18R and 14H structures remains to be established. In this work, the effects of high temperature annealing on the microstructure evolutions of LPSO structure of as-cast and as-extruded Mg₉₇Y₂Zn₁ alloy were investigated by OM, SEM and TEM. The results show that the as-cast alloy is mainly composed of network-shaped 18R-LPSO phase, stacking faults (SFs), α-Mg matrix and a small number of Mg₂₄Y₅ particles. After extrusion, the 18R phase is rearranged in lines along the direction of extrusion and plenty of fine 14H lamella is precipitated in the matrix. During the early stage of annealing, the 14H phase in the as-cast alloy is nucleated massively in the SFs regions around 18R structure. With transformations from the 18R phase, the 14H lamella develops along the directions of length and thickness, and their volume fraction reaches to the maximum when the alloy is annealed for 30 h. As the annealing process continues, the dissolution of 14H phase into the matrix proceeds at the same time. There is almost no 14H lamella present in the center ofα-Mg matrix but a few remains near the 18R phase in the microstructure of the specimen annealed for 200 h. In case of the as-extruded alloy, however, abundant fine 14H lamella has already been introduced during the hot extrusion. When the annealing treatment is operated, the 18R phase keeps dissolving into the matrix until disappearing completely, while the 14H lamella grows continuously. When the whole matrix is covered by 14H lamella, the development of 14H lamella along the length direction is hindered by the grain boundaries. And only coarsening 14H lamella is observed in the as-extruded alloy sample annealed for 200 h.

A self－formation barrier method using CuX (X=Mn, Ti, Zr, Ru, RuN, WN, Ge, etc.)alloys with various concentration solutes has been extensively investigated to meet the requirements of low sheet resistivity, ultra－thin and high thermal stability for Cu metallization. However, intolerable reactions would take place at the interface of the Cu alloy layer and SiO₂/Si layer before the processing temperature reaches high enough to drive the mass migration of alloy elements to interface. In fact, the reaction of Cu alloy layer with SiO₂/Si layer is almost unavoidable due to that Cu diffuses very fast in Si substrate below 200℃. Among those Cu－based alloys, CuGe alloy system has received particular   attention because Cu can directly react with Ge below 150℃ and forms ε－Cu₃Ge films which exhibit a remarkable resistivity (5.5 μΩ·cm), and the Cu₃Ge films also possess high oxidation resistance and interface bonding performance, so can be used as a good diffusion barrier for Cu as well. However, two major problems prevent it from being put into practice. The first is that the mutual diffusion occures between the Cu₃Ge films and the Si substrates above 400℃, and lead to a notable increase in resistivity. The second one is that the germanide film degrades morphologically at 350℃. Therefore, according to the deficiencies existing in these Cu－based alloys, the main objective of the present research aims at taking advantage of the selective reaction characteristic of Cu, Ge and Zr elements to achieve a controlled interfacereaction behavior of Cu/Cu(Ge, Zr)/SiO₂/Si multilayer. The multilayer structure was characterized by FPPT, XRD, TEM, XPS and EDS. The results showed that the reaction sequence of the atoms in Cu(Ge, Zr) films and adjacent layers affected the thermal stability of Cu/Cu(Ge, Zr)/SiO₂/Si multilayer structure. Under the temperature of 200℃, Ge atoms reacted selectively with Cu film and produced ε－Cu₃Ge phase which exhibitted a remarkably low metallic resistivity, and the Cu₃Ge phase could be used as a good diffusion barrier. With further increasing annealing temperature (above 450℃), Zr atoms precipitated at the interface or grain boundary of Cu₃Ge layer and reacted with silicon oxide further to form stable and ultra－thin amorphous ZrO_x/ZrSi_yO_x compounds. So the Cu₃Ge layer combined with the amorphous ZrO_x/ZrSi_yO_x compounds provided superior barrier properties in reducing Cu diffusion into Si at high annealed temperature.

Titanium has long been of interest as hydrogen storage material since titanium has a high affinity to hydrogen isotopes. Titanium deuteride or tritide is an important nuclear material used in the field of nuclear technology. Investigations concerning hydrogen－titanium system seem to mainly focus on the hydrogen thermal desorption spectra so as to study hydrogen desorption kinetics from metal hydride and to determine the rate－controlling step, but little is known on the evolution of its compositional changes under a much more un－equilibrium condition. In the past two decades, the intense pulsed ion beam (IPIB) technique has received extensive attention as a tool for surface modification of materials. Compared with conventional ion implantation, IPIB irradiation into materials possesses a higher energy density with shorter pulse width and be typical of more intense thermal－mechanical effect. From such a point of view, considering the features of extreme high heating and cooling rate of IPIB, IPIB as a method to evaluate the stability characteristics of titanium hydride film is utilized in order to determine a predictable behavior of the film's evolution under an extreme un－equilibrium external condition. In current study, TiH₂ films irradiated by intense pulsed ion beam have been investigated by using scanning electronic microscopy, surface profilometer, X－ray diffraction and slow positron annihilation, in order to evaluate the effect of irradiation with pulsed ion beam on the microstructure of TiH₂. Three sets of TiH₂ films are irradiated several shots at energy density ranging from 0.1 J/cm² to 0.5 J/cm². No noticeable phenomenon of melting and change of phase structures have occurred to samples under irradiation of 0.1－0.3 J/cm². However, phenomenon of melting and indication of cracking has been detected on the surface after energy density reaches 0.5 J/cm².Besides, desorption of hydrogen from the film, and a titanium hydride with a body centered tetragonal structure (bct), seldom reported by researchers and formed under extreme conditions, has also been identified only after energy density of IPIB reaches 0.5 J/cm². S parameter of slow positron annihilation reflects that the crystal defect structures have been greatly changed by IPIB irradiation, in which S parameter reaches a large value at 0.3 J/cm² with 1 shot, while a small one at 0.5 J/cm² with 5 shots.

The dense 304 stainless steel coating material was fabricated by cold spraying technology.The influence of deformation temperature on hot deformation behavior of cold sprayed 304 stainless steel coating material was investigated by thermo－mechanical simulator.The results showed that deformation resistance of cold sprayed 304 stainless steel coating material reduced with the increment of deformation temperature. The steady－state deformation resistance reduced from 315.4 MPa to 187.9 MPa when deformation temperature increased from 1000℃ to 1150℃ with deformation rate 20 s^-1 and deformation reduction 17.5%. The microsturcture of deformation sample might be divided into easy, difficult and free deformation zones. The area of easy deformation zone increased and area of difficult deformation zone decreased when deformation temperature increased from 1000℃ to 1150℃. Recrystallization occurred at free deformation zone without cracking at 1150℃. DSC curve showed that phase transition of cold sprayed 304 stainless steel coating material occurred at 1237－1265℃. The microhardness of cold sprayed 304 stainless steel coating material was 313.3 HV_0.2, which was relatively high. The microhardness of deformation samples reduced from 332.8 HV_0.2 to 244.8 HV_0.2 as the deformation temperature increased from 1000℃ to 1150℃ with deformation rate 20 s^-1 and deformation reduction 50%. The hot temperature deformation equation of cold sprayed 304 stainless steel coating material was obtained with deformation temperature 1000－1150℃ and deformation rate 5－20 s^-1. The value of hot temperature deformation activation energy was 464 kJ/mol under the deformation conditions.