The transformation of the massive ferrite, besides the lath one, was observed in the low or medium carbon ahoy steels under middle temperatures. The massive ferrite consiste of densely dislocated substructural chunks, which are equi-axial or irregular on three dimensional morphology. They nucleate and grow noncoherently either in the interior or along the boundary of grains. No definite orientation,namely neither habit plane nor growth orientation, was found during γ→a transformation. The carbides of different arrangements which exist certain orientations and habit planes may be presented in the chunks with the decreasing growth temperature. Some island constituents rich in carbon which is composed of twinned martensite or martensite with retained austenite at room temperature may be also formed in or at the massive ferrite chunks or along the grain boundaries. The two above-mentioned orientations between the martensite and matrix are the relationship of K-S and N-W. It seems to be considered that the formation of middle temperature massive ferrite may be resulted by the γ→α transformation of a short range diffusion of Fe atoms accompanied with a long range diffusion in the way of island rich in carbon or carbide as well

The effect of addition of Mg on the creep behaviour of Ni-base wrought superalloy has been investigated. It was found that the trace Mg added may cause the alteration of continueous lath carbide into discontinueous massive one at the grain boundaries. It may also promote the spheroidization of the grain boundary carbide, decrease the diffusion coefficient of grain boundary and increase the activation energy for creep. The grain boundary energy and the boundary energy between grain boundary carbide and matrix are decreased and bonding strength of interface increased. Thus, the creep property and the creep-rupture life as well as the stress exponent of creep of the superalloy may be significantly improved by the impediment of the boundary sliding and the prevention of the nucleation and propagation of cracks.

The transformation of the equal atom Ni-Ti shape menory alloy has been studied at 150℃ by means of X-ray diffraction, internal friction, electric resistance and TEM. It was shown that two kinds of phase transformation, namely, of the martensite and the R-phase in the alloy are done between 40-50℃. The structure of martensite and of R-phase is distorted monoclinic B_(19) and B_2 respectively. The Rphase does not reveal a pre-transformation and remains relative stable till -185℃. Thus, the phase transformation in an equal atom Ni-Ti alloy takes place as:β(?)β+R+M(B_(19))(?)R+M(B_(19)).

The phase transformation of Ti-4Al-7Mo-10V-2Fe-1Zr metastable β-Ti alloy has been studied by TEM. The results showed that the athermal ω-phase exists as quenched; the phase transformations undergo in aging at various temperatures as: below 500℃, β→β+ω (isothermal)→β+α; below 400℃, α-phase growing uniformly; between 400-500℃, no more α-phase altered from isothermal ω-phase first uniformly growing, yet selectively growing along the prior β-phase boundaries and at the local crystal defect sites;and beyond 550℃, direct reaction β→β+α and inner twinns forming in the most α plates which decrease in amount with the prolonged aging, then vanish finally. The ledges and displacement at the edge of the α plates were found to follow the above-mentioned process. It was indicated that the orientation relationship between β and α seems to obeythe Burgers' relationship no matter how the aging condition. Only one specimen was revealed the arced spots in the selected area electron diffraction pattern which may be caused by the precipitation of TiH_2.

An investigation was made of the dynamic recrystallization of TC6 Ti alloy by optical microscope and TEM. The three-dimensional dynamic recrystallization diagram of the alloy was establisbed and the optimum hot-deformation parameters for a uniform and fine size grain were determined. An discussion on the experimental results together with the static recrystallization theory is described.

The hydrogen storing property of either binary Ti-Mn or similar polynary system Ti alloys has been investigated. It showed that TiMn_(1.5) and a variety of Ti_(0.8) Zr_(0.2) Mn_(0.8) Cr_(1.0) Fe_(0.2) and Ti_(0.8) Zr0_(0.2) Mn_(0.8) Cr_(1.0) Co_(0.2) alloys are characterized by easy activation, abundant hydrogen absorption beyond 200 mL/g and reversible desorption more than 160 mL/g at 20℃ under atmospheric pressure, as well as cheap cost for preparation. It seems that such alloys may be prospective.

The interracial structure and cohesion strength of Ag-Cu bimetal composite material, obtained by hot-prossing, has been examined. X-ray diffraction patterns show that a binary solid solution containing Ag or Cu respectively is found on each side of the interface. The fracture surface of the tensile specimen made of such bimetal composite material lies on the Ag side of the interface, and the interface itself does not split. The Seach's quasi-chemical method, which is modified to evaluate the cohesion strength of the bimetal interface, gives the theoretical strength of 287.5 MN/m~2, which is higher than that of pure Ag. This is in agreement with the experimental observations. It seems to be concluded that the hotpressing is available to produce a stronger interracial cohesion of such bimetal composite material.

Ribbon specimens were prepared from Fe_5Co_(73)Si_(10)B_(12) amorphous alloy and quenched, annealed or rotational field annealed separately. According to the variation on the magnetization and the magnetostriction figures with different annealed states of them, the magnetic anisotropy induced by the spontaneous magnetization field may be released by the rotational field annealing for such ahoy of which the Curie point is lower than the crystallizing temperature. Th ereason why the amorphous ahoy as-quenched is magnetic anisotropy has been analyzed and discussed.

The variations of the magnetostriction in certain nearly zero-magnetostrictive metallic glasses with annealing and temperature were studied. It was found that, with the increasing of annealing temperature, the magnetostriction goes up then down and contains some reversible component; with the increasing of measuring temperature, it goes up to a small plus value and then down to zero at Curie temperature. The experimental phenomena were interpreted roughly in the light of concepts of structure relaxation, initial crystallization and the single-ion and twoion models about magnetostriction.

Effects of the as-cast crystaline structure and segregation in Cu on the coercivity of Sm(Co, Cu, Fe, Mn)_(7.8) permanent magnets have been investigated. Experimental results showed that the crystalline structure of the ingot is different with different cooling rates. In the equi-axed grain structure, the inner of the grain is deficient in Cu; free Cu concentrates on the grain boundaries, where an amount of high temperature phase of hexagonal structure of Sm_2Co_(17-x)T_x is preserved, resulting in a decrease in the coercivity. In the fine-columnar grain structure, no serious segregation in composition has been observed. Magnets after sintering and solution treatment exhibit the cellular microstructure; precipitated Cu and SmCo_(5-x)T_x phase rich in Cu disperse on the cell-wall. They probably play, in the course of magnetization reversal, the role of pinning the domain wall, hence, giving high coercivity.

The expression of the elastic field round the outside of the disk inclusion has been deduced analytically by the method of the harmonic and biharmonic potentials. The formulation of the stress intensity factors of the disk inclusions in terms of its eign-strains is resulted. The aspects of the results obtsined as well as its availability have also been discussed.

Experiments were conducted in the stress corrosion cracking (SCC) of the austenitic stainless steel in boiling 42% MgCl_2 solution under compressive stress using three different types of specimens with surface residual compressive stress; of U-bend or of notched modified WOL. The SCC was observed on them after 110, 73—100 or 262—324 h respectively. Their fracture surface are charaterized by the stratified rock structure and the striation-like pattern of quasi-cleavage rather than the river marks or the fan pattern under the tensile stress. Almost one order of magnitude of the incubation period of SCC under the compressive stress is prolonged beyond that under tension. Because the cracking propagates very slowly and spreads hardly to distinguish, the SCC under compressive stress does not be revealed, if it is under tensile stress simultaneously. The behaviour of hydrogen in SCC of such system has been also discussed.

The verified formulation for determining the residual stress intensity factor (SIF) in the DCB specimen was deduced as below:K_(IR)=Eφh h~(1/2)/2 3~(1/2)which can be easily got by measuring the curvature φ of the half-specimen and does not vary with the crack propagation. It was found that the value K_(IR) for LC4 Al alloy is markedly influenced by the aging temperature, e.g., below 120℃, its K_(IR)>K_(ISCC), the residual SIF can not be effectively dissipated, and its K_(IR) may be much lowered only by an additional fractional aging up to 160℃. The influence of the heat treatment upon the value K_(IR) of LC4 Al alloy has been described.

The coercivity of dual phase steel 09MnNb with various heat treatments was measured. The plots of H_c vs T_a and H_c vs MVF were given.

According to the facts of no systematic extinction and the sequencc of the occurrence of the reciprocal planes in a series of electron diffraction patterns obtained by tilting around the [110]~* and a~* axes of μ-phase, the lattice type of μ-phase in the superalloy GH302 has been determined tobe a simple hexagonal lattice with severe stacking faults in [001] direction and having the lattice parameters of a=4.75 (?) and c=25.8 (?).

A computer program for determination of orientation relationship between the second phase and the matrix is presented. Some examples are given.

Improved rheocast process was studied for performing the high quality of Al alloy casting made of the preparation of the metal slurries. The measures taken for reducing the porosity of die casting have been investigated. It was shown that the conventional diecasting is not to be compared with the rheocasting for ZL104 and ZL702 as well as other Al alloys. The hydrogen content may be much lowered, and the bulging surface on the casting may be much improved after heat treatment.

The maximum shear stress yield criterion in macromechanics was given by Tresca (1864), and the critical shear stress law of the crystal was established by Schmid in 1924. Their criteria agree with experimental data of some materials and crystals. But owing to complexity and variety of slip in materials and crystals, there exist some deviations from Tresca criterion of yield and Schmid shear stress rule of slip for many materials and crystals. The researches made by a number of investigators show that some shear stress may affect the plastic deformation both in yield of isotropic material and in slip of crystal.A macroscopic twin-shear-stress yield criterion was proposed by the author (Yu Maohong) in 1961. Twin-shear-stress yield criterion assumes that yielding begins when the sum of the two larger principal shear stresses reaches a magnitude C. Thus the yield function isf=τ_(13)+τ_(12)=σ_1-1/2(σ_2+σ_3)=C, when τ_(12)≥τ_(23);f=τ_(13)+τ_(23)=1/2(σ_1+σ_2)-σ_3=C, when τ_(12)<τ_(23)The multiple slip systems and non-Schmid effect of slip in crystals were observed for many years. Taira and Hayashi show that the crystal in polycrystalline metal do not deform in simple slip systems but on multiple slip systems. Since slips on simple systems would create gaps at the grain boundaries and this is not the case, A crystal in a polycrystalline aggregate must slip on more than four slip systems in order to satisfy mechanical condition. So a unit octahedron, a unit dodecahedron, a 24-hedron were used to represent the multiple slip systems. In this paper, the twin-shear-stress yield criterion is generalized to slip of crystal and polycrystal. A critical twin-shear-stress criterion of slip in crystal is proposed here. The rhombic dodecahedral model and orthogonal octahcdral model are proposed to represent the multiple slip systems of crystal under complex stress state. The critical twin-shear-stress criterion of slip in crystal assumes that the slip of crystal begins when the sum of two shear stresses in dodecahedral multiple slip systems reaches a critical value. It seems that the critical twin-shear-stress criterion may be used to expound multiple slip systems and the non-Schmid effect of some crystals and polycrystals.

An attempt was made by chemical process to produce the RE coating by solid-gas interfacial diffusion-infiltration on steel 20 and Armco iron. The chemical composition of coating and the distribution of Ce and La along the depth beneath the surface of the steel specimens have been analyzed by ion-probe, SEM energy spectrum and fluorescent X-ray. It is shown that RE is remarkably influenced upon the carbonitriding process.

The ductile-brittle transition temperature, T_B, of certain Fe-, Pd-and Ni-base glasses as wel as Pd_(80)Si_(20) and Cu_(57)Zr_(43) has been determined. The influence of the transition metals and metalloid contained on T_B and the relationship between TT-T-diagram and the transition behaviour have also been investigated. On the basis of the kinetics of their transition, the evaluation of their own activation energies and the proposal of their electron concentration dependence are presented.

The thermal stability parameters of metallic glasses Pd_(83.5-x)M_xSi_(16.5), where M denoting Hf, Ta, W, Re, Os, Ir, Pt, Ru, and Rh, as both melt quenched and annealed states T_g, T_x, T_p, T_m, T_(liq) and T_(rg), as well as glass transformation and crystallization activation energy, heat of crystallization, Twyman constant, etc. have been determined by DSC and DTA. It is found that the thermal stability of metallic glasses composed by the preceding transition metals, e.g. Hf, Ta, W and Re is increased obviously, hut by the later ones, e.g. Os, Ir, Pt, Ru and Rh, much less influenced. These behaviour has been discussed by the Gaskell's model and Engel-Brewer electron theory of transition metals.

An over-optimistic assessment in accuracy is often resulted from the magnetization measurement by the current standard methods for the feebly magnetic materials due to ignoring the significant influence of demagnetizing field on the ballistic method. Analysis is reported on the effect of demagnetizing field upon the feebly magnetic measurement, and calculation is presented to two kinds of ballistic demagnetizing factors which are about non-magnetic cylindrical specimen itself and about its measuring coil. Thus, the errors of H and M measurements in regard tO the demagnetizing field and their correct method as well are given. It may be suggested that a set of standard dimensions for the feebly magnetic measurement is available.