When Sn segregated at grain boundaries of high induction oriented silicon steel, no remarkable interaction between Sn and other elements was observed. At the starting temperature of secondary recrystallization, 950℃, a certain Sn still segregates at grain boundaries. Sn seems to act as a supplemental inhibitor through grain boundary segregation. According to theoretical analysis, an addition of Sn may decrease the secondary recrystallization temperature of high induction oriented silicon steel, and it is in agreement with the experimental result.

Microstructure of the deepest zone of laser fursxed high speed steel W6MoSCr4V2(M2) was found to be so fine as the chill zone of a solidified ingot. When narrower chill zone formed, the long columnar dendrites grow into the melt and then the fine equiaxed cellular structure reveals in upper melt region nearby surface. The substructure of cellular grains and dendrites was observed to consist of martensite and retained austenite, while the carbides as M_6C, Cr_7C_3 and MC distributed at their interfaces. It is believed that the high microhardness, HV_(0.1)=865—960, of the laser fused structure of the alloy is due to the occurrence of martensite.

The microstructure, tensile properties at 20—950℃ and creep rupture properties at 700—900℃ in a Ni_3Al-Fe based alloy after high-temperature deformation have been studied. The results show the microstructure of the alloy is composed of γ′ and β phases. The grain size and yield strength of the alloy is stable ≤600℃. And it is ductile at high-temperature. The creep in the alloy at 700—900℃ is controlled by dislocations climb, and creep activity energy is 439 kJ / mol, stress factor is 4.

A new model, called A-model, was developed based on the hypothesis of polyhedral grains. The probability functions and the method to calculate 3-dimensional grain size distribution functions using the A-model are given. The theoretical analysis and experimental test have demonstrated that the A-model reduces the systematical error radically and gives much better results.

Experimental investigation was carried out of hot deformation behaviour of Nb-bearing low carbon steel 14MnNb by Gleeble 1500 simulator. Regressive analysis was made of the relationship between deformation conditions and steady flow stress during hot deformation and peak flow stress correponding to dynamic recrystallization. Clarification was also described for the influence of strain-induced Nb (C, N) precipitation on the activation energy of formation. On the basis of analyzing the processes of dislocation multiplication and recoveries from cross-slip of screw dislocation and from climb of edge dislocation during plastic deformation of metals, the theoretical model to predict flow stress under the conditions of dynamic recovery and recrystallization occurred simultaneously was developed. The prediction about flow stress, in practice, under various deformation comditions by the model seems in fair agreement with the experimantal results.

The formula for calculating included angle between polyfamily plane traces in foil of lattice systems under both zero tilt and non-zero tilt states was deduced and verified by certain practical examples. The method may be available to index the plane traces of slip, twin and other defects, especially to determine such plane defects as twin planes of {011} and {013} occurred simultaneously in M_7C_3.

The symmetrical push-pull fatigue tests at strain of 2×10~(-3) for different slip orientation A1 single crystals, 99.999% purity, were carried out at room temperature in air on 5 kN Shimadsu 4825 servo-hydrauhc machine. The peak stresses of various cycles were measured by a digit voltmeter and the stress-strain hysteresis loops for selected cycles were recorded using an X-Y recorder. The energy losses, friction stresses, back stresses and shape parameters of hysteresis loops were measured from the hysteresis loops obtained. The morphology of fatigued specimen surfaces was observed under SEM. The results found that the parameters above are affected awfully by the orientation of crystals. The crystals with multiple.slip orientation, in comparison with single one, are of numerous initial hardenability, saturated stresses and energy losses, while the hysteresis loops shape of single slip orientation crystals become even more rectangular. The relation among parameters above mentioned and contact between them and internal structure of the materials were discussed in belief.

Five fields corresponding to the primary crystallization of PrCl_3, Sr_3PrCl_9, α(SrCl_2, CaCl_2),α_1(CaCl2, SrCl_2) and β_2(SrC12, CaCl_2) respectively, six univariant lines related to the secondary crystallization, one ternary eutectic (48.0 wt-%PrCl_3, 23.5 wt-% SrCl_2; 590℃) and ternary peritectic point (45.5 wt-%PrCl_3, 24.5 wt-% SrCl_2; 614℃ ) were determined by DTA. Attempts were also made to explore the rule governing the alteration in the phase diagram containing rare earth chloride, formation of compound and its stability by means of the theory of polarization and counter-polarization.

Partially amorphous Ni_(60)Nb(40) alloy coatings was made using 1.91 kW cw CO_2 laser melt-quenching, and fully amorphous using 4.5 kW and 4.9 kW. The corro sion resistance of the amorphous layer was improved by adding Cr. Potentiodynamic polarization curves show that Ni_(50)Nb_(40)Cr_(10) is much more corrosion-resistant than stainless steel 18-8.

The depth profile of composition, chemical state of elements and morphology of as-received and activated amorphous Fe_(80)Zr_(12)B_8 alloy ribbons have been studied by means of Auger electron spectroscopy, X-ray photoelectron spectroscopy and scanning Auger microprobe combined with Ar ion bombardment. Both dull and free sides of the as-received ribbons were covered with an iron oxide layer. While a pronounced surface segregation and oxidation of B were observed on both sides of activated ribbons, the fine microcrystalline α-Fe was precipitated as well as B and Zr were oxidized selectively in subsurface layer. On both sides of ribbons, a porous surface structure was formed. The BET surface area was measured to be increasing from 0.11 to 2.68 m~2/g. The principal mechanism of in situ activation has been discussed.

A superhard α-Si_3N_4 film, deposited on metal substrate, was made by laser chemical vapour deposition adopting a kW-level high power CO_2 laser, Most films are of fine grain Si_3N_4. They join the metal substrate in strong bond. The films have super hardness, excellent resistances to wear and corrosion, etc. Their thickness may be controlled within 5—30μm.

Specimens of 1Cr_(18)Ni_9Ti stainless steel were pre-pitted and fatigue, some in 6%FeCl_3 solution and others in air, untill N>1×10~6 cyc. The geometric parameters, e.g. depth and diameter, of all pit were accurately measured by quantiative metallography. They were found to be effective on crack initiation. The pit-induced crack initiation is mainly due to mechanical factor for stainless steel, but quite different than carbon steel. After the specimens failed, the morphologies of pit bottoms were also examined by SEM for determining the initial sites of cracking. Thus, the mechanisms for pit-induced corrosion fatigue crack of these two typical steels were discussed.

Crystal structure of γ-Li_xFe_2O_3, inserted Li electrochemically, was studied by Mossbauer spectroscopy together with X-ray diffraction, XPS and electrochemical method. On the insertion of Li with low current density, the crystal structure is keeping original spinel; while with higher current desity or by thermal activation, owing to violent movement of Li~+ ions, part of crystal structure transforms into rock type similar to face—centered cubic structure of ferrous oxide. The transition channel during insertion of Li and limitation of Li~+ ions to be inserted were discussed.

The measurements of the activation time and the breakdown potential of surface films formed on stainless steel 304 in passive or transpassive potential range, followed by post-treatment in Na_2MoO_4 containing solution or not treated, were carried out. The results show that the resistance of transpassive film against the activation dissolution in acidic solution is much higher than that of passive film, and the breakdown potential of transpassive film can be strikingly enhanced by post-treatment. In addition, the effects of potential and post-treatment on the composition of surface film were investigated by means of AES and XPS analysis, and the relationship between the composition and stability of film was discussed too.

The Nd_(14)Fe_(73)Co_6B_7 magnetic powder with high coercivity was effectively made of its ingot by hydrogenizing-disproportionating-dehydrogenizing, so called HDD process, under H_2 atmosphere. The high coercivity of the powder was found to be dependent on the decomposition of Nd_2Fe(Co)_4B phase during hydrogenation and consequent upon recrystallization during dehydrogenation. And the contrast of grain size in between original ingot powder and recrystallized one, from 10—50 down to 0.3--1μm, may be the principal cause for this improvement.