The behaviour of corrosion fatigue crack propagation in 4330M steel in distilled water has been investigated. The rate of stress corrosion crack propagation in distlled water, the fatigue crack propagation in argon and the corrosion fatigue crack propagation in distilled water with stress ratio R=0.2, 0.6, 0.7 and 0.8 were measured. The rate of stress corrosion crack growth per second da/dt and the rate of fatigue crack growth per cycle da/dN are related to the crack tip stress intensity factor K and cycle range of stress intensity ΔK respectively.A BASIC computer program has been developed to calculate the cyclic rate of stress corrosion crack propagation (da/dN)_(SCC) with the experimental data of the time rate da/dt. The cyclic rate of corrosion fatigue crack propagation (da/dN)_(CF) based on both the "linear summation model" and the "process competition model" were also calculated by computer respectively and compared with the experimental data. It is shown that the experimental results consist the "process competition model" suggested by I. M. Austen. However, a modification to the "process competition model" was represented in which an interaction term is added.The basis of this modified "process competition model" is that: the fatigue and the stress corrosion crack growth process including their interaction terms are mutually competitive and that the crack will propagate at the fastest. Thus, the cyclic rate of stress corrosion fatigue crack growth (da/dN)_(CF) is (da/dN)_(CF)=(da/dN)_F+(da/dN)_(int F) or (da/dN)_(CF)= (da/dN)_(SCC)+ (da/dN)_(int S) where (da/dN)_F and (da/dN)_(SCC) are the cyclic rate of fatigue crack growth and of stress corrosion crack growth respectively, and (da/dN)_(int F) and (da/dN)_(int S) are the additional value of da/dN due to the interaction between the environment (water) and fatigue on (da/dN)_F and (da/dN)_(SCC) respectively.Some discrepancies of experimental results in quantitative understanding of corrosion crack growth rate were explained and treated uniquely this model.The results presented here shows that the steel used in this paper is appropriate for systematic study of mechanisms of stress corrosion fatigue crack propagation.

Several nearly zero-magnetostrictive non-crystalline toroidal samples have been examined for the shift of hysteresis loops changed by the magnetic operations prior to their measurements. It is shown that the loop shift of the samples annealed over 420℃ is related to the precipitation of crystallites with high H_c from the non-crystalline matrix. It can be eliminated to a certain extent by means of some suitable demagnetizing or shock-magnetizing, and the H_c of the shift-eliminated loops varies with the operations preformed.

The compression effect on domain structure of grain oriented 3%Si-Fe was studied. As well known that if a compression is applied along rolling direction, then the domain magnetized along [001] would be energetically unfavourable. In that case the transverse domains magnetized along [100] or [010] are energetically favourable. So the latter would grow by the wall moving of the nuclei of transverse domains and become the main domain structure. As for the former main domain structure, then it would be degenerated into supplementary. Such stripe like pattern, which is parallel to [110], is so called transverse stripe pattern. With further increase of compression, these transverse stripe pattern would be broken into two groups of differently aligned tilting domain fragments, gradually. There are some correlations between the alignment of these tilting domain fragments and the crystallographic orientations. These two groups of tilting domain fragments intertwine with each other in rows and they are looked ike "λ". The higher the compression, the greater the volume fraction of "λ" domains. The row width and the space of domain fragment itself are also reduced with increase of compression. The cause of formation of such domains is discussed in the light of energy consideration. A model of "λ" domain structure is proposed in the present work.ě

One of the chief factors influencing the incipient melting in Hf-bearing DS Ni-base superalloys was found out to be Ni_5Hf-phase. The melting peak at 1135—1160℃ showing Ni_5Hf-phase more than 1.0 v.-% has been determined by DTA on heating. A distinguishable segregation of Ni_5Hf in both ends of the directionally solidified ingots by PD technique was shown, and their sensitivities to incipient melting are quite different consequently, The incipient melting of Ni_5Hf-phase may induce the solution of γ+γ′ eutectic and M_3B_2. It was also obtained that the low-carbon or carbon-free Hf-bearing alloys have stronger tendency to incipient melting, as well as the slow cooling microstructure and the increasing rate of solid solution temperature are sensitive to it. The reduction of rupture strength of the alloys may be caused by the presence of incipient melting of Ni_5Hf more than 3 v.-%. Their rupture is propagated mainly along the interface between the melting zone of Ni_5Hf and the eutectic γ′. By means of pretreatment at 1150℃ for 8h, the Ni_5Hf-phase may be completely eliminated, thus the incipient melting of the Hf-bearing alloys may be effectively brought under control.

The effect of trace Cr on the precipitation, critical nucleation temperature T_c′ and structural parameters of a commercial purity Al-5.0Zn-1.8Mg alloy has been investigated by means of hardness test, optical microscopy and TEM. It was resulted that the trace Cr may facilitate the heterogeneous precipitation and the raise of T_c′, as well as may also retard the growth of GBP, PFZ and MPt after lower temperature aging (T_a≤160℃), however, it may accelerate them after aged under elevated temperature (T_a≥180℃). The above-mentioned behaviour seems to be explained by the dual mechanism of the interaction of Cr with vacancies.

According to the matrix analysis of electron diffraction patterns and to the analysis and calculation of structure amplitude for ordered structure δ-phase, the confirmation was made of that the δ-phase of the Widmanst(?)tten structure in Ni-Fe-Cr-Nb alloy grain is identical with the orientation relationship and formation mechanism shown by Ⅰ. Kirman and others. But certain δ-phase of cellular structure does not have such relationship and there is yet some imperfectly regular ones. It was also found that the Ni and Nb atoms may be imperfectly distributed in order within some cellular δ-phase.

The formation of zigzag grain boundary and its influence upon mechanical properties in nickel-base wrought superalloy with high γ′-phase content has been investigated. It was shown that the γ′-phase precipitation at the grain boundary during controlled cooling after solid solution treatment is the dominant factor for the formation of zigzag grain boundary and the grain boundary γ′-particles are coherent with the one of neighbouring grains and incoherent with the others. Thus, a model of the formation of zigzag grain boundary was proposed. Factors influencing the crookin8 of grain boundary have been also studied.

The Sr modification of an Al-Si-Cu-Mg hypoeutectic cast alloy has been investigated by using SEM with both wavelength and energy dispersive X-ray spectrometers. It is found that the Sr addition does not affect the size of Al-Si eutectic cells in the alloy, but changes the morphology of eutectic Si. Hence, the Sr modification is resulted not by the change in nucleation of eutectic Si, but by that in mode of its growth. An available new idea "modification threshold value" was also proposed.

The work done in the formation of plastic zone at the crack tip has been evaluated with a simplified dislocation model and then the critical crack extension force may be calculated. Under various types of deformation, the magnitudes of work done in the plastic zone formation are different due to their different stress distributions at the crack tip. In view of the abovementioned approaches and of consideration of the correlation between K_(Ⅰc) and K_(Ⅱc) for a small scale yielding material, it has come to the conclusion: IK_(Ⅱc)>K_(Ⅰc), which is consistent in the experimental results. The ratio K_(Ⅱc)/K_(Ⅰc) and the temperature dependence of the mechanical properties of materials have been also discussed.

The double layer capacitances and zero charge potentials of certain solid metal electrodes in LiCl-KCl melts at 450℃ have been measured by an A. C. bridge method. The zero charge potentials, ε, for Pt, Ag, Cu and Al electrodes are +0.2, -0.4, -0.6 and -1.0 V respectively which was estimated by the minima of C-V curves. If these data together with selected ones from published works in NaCl-KCl melt at 700℃ plotted against their own ionization free energy, △Z_2, a straight line, paralleled that in aqueous solution, may be drawn and expressed as:ε=0.305(△Z_2/q)+Awhere q——1 mole electron charge and A——constant.It indicates that the zero charge potentials between two chlorides molten salt are alike of same solid metals but differ of different ones, and their difference is similar to that in aqueous solution. Thus, it seems to be proposed that the zero charge potentials of the solid metals in molten salts are only determined by the nature of metals themself.

The solubility of C and the activity coefficient of Cu and Fc in Fc-Cu-C and Fc-Cu-Co-C systems at 1550℃ were calculated. The results indicate that the activity coefficient of Cu increases and of Fe decreases with the increase of C content. On the basis of data obtained, the first and second order activity interaction coefficients in Fc-Cu-C systcm and interaction coefficients of free energy or enthalpy at constant activity as well as the partial molar heat of mixing of C affected by the Cu content were estimated. Compared with the thermodynamic functions of other Fc-j-C systems after previous works, the regular correlation between these thermodynamic properties and the atomic number of j element seems to be noticeable.

The effect of the melt superheat on the solute distribution coefficient and the critical condition of the interface morphology on the directional solidification has been studied. It is found that the actual distribution coefficient of solute is a function of liquid state. An increase of superheat of the melt causes the increase of actual distribution coefficient for such elements of K_0<1, and the decrease of the critical conditions of G/R associated with the stability of the solid-liquid interface morphologies which seems to be available to improving the directional solidification.

A new intermetallic compound PrPd_5 was synthesized from individual pure metals. Its lattice parameters in comparison with MoAl_5 of well-known WAl_5-type structure are:a c c/aPrPd_5 4.97 8.996 1.81MoAl_5 4.89 8.80 1.80

An approximately functional graphic method and formulae for X-ray line frofile analysis of micro-distortion and mosaic structure were developed and a complete set of geometric broadening correction curves graph for this purpose was prepared.Considering the X-ray diffraction line pairs mostly selected in working on martensite and austenite materials and Ni-base alloys, based on the 5 radiations widely used in the laboratories, 35 kinds of separating m, n curves were plotted.

Certain typical examples used for the explanation of two problems are described: the allowable limits of starting value variation for the calculation of binary phase diagram by iteration and evaluation of the method of aUotropic equilibrium point for selecting starting value. It is proposed that the method of number direction approximation and the method to judge the real phase boundaries seem to be available for the calculation of binary phase diagrams.

A method is proposed for ascertaining the lattice stability parameters, offering an example of 5 binary phase regions in Cu-Ag and Pb-T1 systems, on the basis of a few thermodynamical data and the state function properties. The calculated binary phase boundaries by using these parameters are in good agreement with the experimental results. Thus, the phase equilibrium among the solid solutions with fee structure in Cu-Ag system has been discussed.

The variation of maximum solubilities, C_α and C_β, of the element of group IVA such as Si, Ge, Sn or Pb in α-and β-Ti have been discussed by statistical analysis, It is shown that the variations of C_α and C_β are controlled simultaneously by the metallicity of the element and by the difference between the atomic radii of Ti and the element of group IVA. The effect of metallicity on C_β is more predominate than that on C_α, while the effect of difference between atomic radii on C_β is less than that on C_α. This variation seems to be of common significance.

The variation of maximum solubility C_α of S, Se or Te in α-Ti has been calculated by solving the proposed equation. It was shown that the equation is also available to Po, its C_α =0.21 at.-％ and the effective electric charge z~*=5.26. The maximum solubility C_β of S, Se, Te or Po in β-Ti was estimated to be 0.13, 0.24, 0.29 or 0.32 at.-％ respectively by the correlation between C_β and C_α. Thevariations of C_α and C_β of the elements of group VIA are controlled by nonmetallicity and the difference between the radii of atoms of these elements and Ti, and mainly by their non-metallicity. C_α and C_β have good linear relationships with the difference between electronegativity, the ratio of electric charge and radius of Ti or these elements, the ratio of electric charge and radius of these elements and the difference between atomic radii of Ti and these elements. C_α and C_β decrease linearly with the increase of these parameters.

The surface tension of Cu-Sn alloy was determined by the sessile drop method. The anomalous temperature dependence on the surface tension of Cu-37％ Sn alloy in the testing range is perhaps due to the atomic cluster relating to γ-phase in the liquid alloy.

Both three dimensional displacement and the strain function of metal in the deformation zone of continuous tube rolling under the condition of straight line and circular arc side wall pass were confirmed by Ritz's method to solve the minimum energy equation. The calculational formula of rolling pressure and moment was deduced by the three dimensional deformation analysis using the energy equilibrium principle. The experiments in cold rolling Al tube and hot roiling steel tube verified that the theoretically calculated value is identical with measured one, Thus, this formula seems to be available to the engineering practice.

An investigation was carried out on the premature "pop-in" events of rail or wheel steels. It was shown that these are caused by the segregation of elements such as Si, Mn, S, etc. in steels used. The probability of the premature "pop-in" event, p, may be: p=10.08-4.8534lg K_(Q1) where K_(Q1) donotes the specified fracture toughness. The proposal seems to be made that (1-p) is available for the reference of their safety inspection.