A simple type of diffusion couple was designed. The compositions of the phase equilibrium α/γ at 1200℃ and 1250℃ in Ti-Al-Cr-Fe quarternary system have been determined by the diffusion couple-electron probe method, and partial isothermal squares for Ti-Al-Cr-Fe quarternary system have been drawn. The results show that Cr has the effect of increasing the solubility for Fe in the α phase and Fe has the effect of increasing the solubility for Cr in the α phase.

Stacking fault energies in Fe-Mn-Si-Cr-Ni and Fe-Mn-Si-Cr-Ni-Co stainless iron-based shape memory alloys are calculated by means of extended dislocation node measurement,and the corresponding values are 25.1 and 10.3×10-7 J/cm2 respectively.

Room-temperature tensile properties of Ti-47Al-2Mn-2Nb alloy with near lamellar (NL) microstructures were investigated at the strain rates between 20 and 1000 s-1 using a self-designed Split-Hopkinson tensile bar setup with a rotating disk. And a comparison was made between static and dynamic tensile properties. It was found that tensile ductility fluctuates within a narrow range with the variation of the strain rate f dynamic elongation is almost the same as the static elongation. But dynamic strengths (d) of the alloy and their strain rate sensitivity are obviously higher than those under static strain rates, and there exists linear relationship between static strength (s) and the logarithm of the strain rate(s= A + Blu), and between d and the strain rate itself(d = C + D). Fractography analysis indicates that the alloy fractures in a mixed mode of predominant transgranular cleavage and minor intergranular cracking under static and dynamic strain rates. Environmental effect is excluded from the main cause for the room-temperature brittleness of the investigated alloy.

The effect of minor boron addition on tensile properties of wrought Ti-47Al-2Mn-2Nb alloy was investigated at strain rates from 20 to 1000s-1 , using a self-made separated Hopkinson tensile bar setup. It was found that the addition of 1.0%B (atom fraction) increases dynamic tensile strength considerably, but does not damage the linear relationship between dynamic tenisle strength and the strain rate. Meanwhile, the addition produces neither obvious improvement on dynamic tensile ductility nor noteworthy change in fracture mode.

The fine fully lamellar (FFL) microstructure and intermedium microstructures in the process of forming FFL microstructure were examined under optical and transmission electronic microscopes. Based on the observation results, the transformation mechanism of FFL microstructure was analyzed and proposed as that the fine γ/α lamellar colonies form at the high temperature in the α single phase region through the precipitating of the α plates on the four equivalent habit planes {111}γ, in each γ matrix grain and then evolve to the γ/α2 lamellar colonies of the FFL microstructure.

Molecular dynamics simulation was carried out to study transformation pseudoelasticity in NiAl alloy with a initial B2 structure, using EAM (embedded atom method) type interatomic potential for NiAl. The evolution of the RDFs and bonded atomic patterns indicate that martensitic transformation took place when external tensile force increased to a certain level.During the transformation, variants could integrate each other under the action of the external force, coherent twinning interfaces were formed between misoriented variants. A reverse process initiated at the coherent interfaces occurred when the external force was withdrawn. With the migration of martensite-austenite interfaces the stress induced martensites transformed back into austenite.

The Monte Carlo simulation method for crystal growth is explored by including the macroscopic temperature, solute redistribution within the liquid phase and the thermodynamics in metal solidification process. A model coupling macro and micro is created to describe solidification structure formation in solidification process. The Al-4.5%Cu (mass fraction) alloy is used in the simulation. Finally, the simulation results are compared to experimental results. It shows that this simulation method is feasible.

Based on the Finnis-Sinclair potential given by Igarashi et al, molecular dynamics simulation of liquid structures of 8 hcp-type metals was carried out. The situation of this F-S potential for description the liquid structures of those hop-type metals was analyzed. Two rapid solidification processes of metal Co were simulated by MD. Using pair analysis technique the effect of cooling rates on microstructure of Co was analyzed.

The behavior of particles at solidification interface of Al/Al2O3 and Al-Si/Al2O3 composites was studied by using the zone-melting unidirectional solidification method. The particles were pushed by S/L interface in most of the composites, but the state of particle engulfment was realized by adding minute elements into an Al-Si/Al2O3 composite. An explanation model based on interfacial energies was proposed. If the contact angle between a solidification front and a particle is more than 90°, the particle can be engulfed into the solid. Otherwise the particle would be pushed.

The compression creep behavior and creep instability of TiAl PST crystals with three orientations at 800℃ were investigated. The results indicated that the creep resistance of PST crystals is strongly dependent on the anglebetween the lamellar boundaries and loading axis. The creep instability is identified to occur in different ways in the samples with the three orientations. For samples with =90°, the creep instability is associated with the spheroidization of α2 and the formation of the shear band during the creep, it may account for the early onset of the tertiary creep in these oriented samples.

The relationship between fracture toughness and notch toughness, tensile ductilities in lath martensite steel has been investigated. The experimental results show that fracture toughness is controlled by microplastisity in the small local region (1 to 2 times the crack tip opening displacements c at critical) ahead of the crack tip, whereas blunt notch toughness, tensile ductility is controlled by austenite grain size (dγ) or martensite packet diamiter (dp). The characteristic distance corresponds to the extent of effective deformed region (2c) resulted from blunting of crack tip. The relationship between fracture toughness and notch toughness 、tensile ductility depends on the relative size of effective influence region (2c) and austenite grain. When 2c> (1 - 2dγ), the fracture toughness coincides with notch toughness, tensile ductility.

The SCC susceptibility of 1Cr18Ni9Ti austenitic stainless steel in 0.75mol·L-1HCl +0.25mol·L-1NaCl solution has been studied by slow strain rate tests(SSRT) and SEM. During the slow rate tensile process, the specimen was polarized with different potential perturbation modes such as potentiostatic, cyclic potential scan and cyclic potential step methods. The results indicated that potential scan rate and step frequency played an essential role in the initiation and propagation of crack. Potential step at high frequency led to much higher cracking susceptibility than potential scan within the same potential ranges.

A method for grabbing and analyzing in-situ images was established to study pitting corrosion in 304 stainless steel. Using a self-developed Visual C++ program, images obtained upon potentiostatic polarization were analyzed. It was found that there was a liner relationship between pitting ratio and reaction electric quantity. Besides, lots of small pits became a larger pit, and grays moved towards smaller values and double peaks were observed on the gray histograms when pitting corrosion happened.

Based on the principles of the electrochemical modifying treatment for molten cast iron, preparing ductile iron in ESR process tinder D.C. condition without adding spheroidizing inoculant alloys has been studied in laboratory. The key operation of ESR for producing ductile iron is to increase the silicon content of consumable grey iron electrode and use CaF2-based slags containing rare-earth chide or alkaline-earth oxide and magenisium fluoride. Under the condition of D.C. reversed polarity, the anodic corrosion reaction silicon at the consumable electrode tip leads to a decrease of ferrous oxide concentrationin molten slag, therefore, the cathodic reduction of magnesium canon or cerium cation at the interface between slag and metal pool happens easily.A small amout of nodulizing element such as Mg and Ce, being transferred from slag into metal pool make graphite spheroidizing in remelted ingot. This new method of producing ductile iron in ESR process seems to be useful for the development of new metallurgical technology.

The Zr-Ni intermetallic compounds coexist with Laves phase in the Zr-Mn-V-Ni alloy. Zr0.5Ti0.5Mn0.2Vo.6Ni1.2 alloy accommodates C14 Laves phase and Ti containing bcc phase. Selected area electron diffraction (SAED) and energy dispersive spectrum (EDS) analysis show the bcc phase was B2 type R phase (Ti0.8Zr0.2)Ni. The lattice parameters and substructure of Laves phase in ZrMn0.2V0.6Ni1.2 alloy varied after Ti substitution for Zr. Formation of non-Laves phases causes the alloying elements redistribution among the coexisting phases. The change of electrochemical properties of Zr0.5Ti0.5Mn0.2V0.6Ni1.2 can be attributed to the Ti substitution for Zr site in C14 laves phase, the formation of (Ti0.8Zr8.2)Ni phase and disappearance of Zr-Ni binarg compound.

Laser surface alloying with carbon was employed to modify the surface properties of TiAl intermetallics. The rapidly solidified "in-situ" wear resistant composite reinforced by titanium carbide was produced in the laser modified surface layer. The microstructure of the laser alloyed surface layer was studied as a function of the laser processing parameters.

A functionally gradient TiC/Ni alloy composite coating was produced by one step laser cladding with pre-placed mixture powder on 1045 steel substrate. The clad layer consists of TiC particles, γ-Ni primary dendrites and interdendritic eutectics. From the bottom to the top of the clad layer, TiC particles exhibit a continuous increase both in size (from 0.8μm to 4.5μm) and in volume fraction (from 4% to 33%), and their morphology changes correspondingly from small globe to coarse flower-like cluster. The rapid coarsening of TiC clusters during the solidification of laser pool results from the collision and sintering of particles. The preferntial engulfing to a small cluster moving at slower speed by liquid/solid front leads to in-situ formation of the gradient structure of the coating.

There are three exothermic peaks and two endothermic peaks in Ni-Al differential thermal analysis (DTA) curves. Three exothermic peaks are respectively attributed to NiAl3 formation by solid-solid diffusion of Ni and Al power, Ni2Al3 formation by liquid eutectic spreading on the surface of Ni power, and Ni2Al3 and NiAl formation by diffusion. Two endothermic peaks are respectively caused by primary eutectic contact melting and later A1 melting, and anti-peritectic reaction of NiAl3.

The influences of nano-SiC on the superconducting properties of Bi2223, especially on the flux pinning have been studied by using XRD, SEM, SQUID, VSM. The results reveal that the nano-particles of SiC do not change the transition temperature obviously. The magnetization areas on the M - H curve, intragranular critical density Jcm and average flux pinning force Fp were improved due to proper amount of nano-SiC addition at temperature 5 K and 77 K. According to these evidences, we can infer that the nano-SiC particles introduced and homogenuosly dispersed in superconducting matrice take the role of effective flux pinning centers.

The visible absorptance of the ultrathin aluminum film has been measured by WFZ900-D4 UV/VIS spectrophotometer. The result indicates that the absorptance is a function of film thickness and has obvious size effect. With decreasing the film thickness, the maximum absorptance appears. Comparing to electric conductivity characteristic of the film,unique structure feature leads to the size effect of the absorptance of the ultrathin aluminum film.