As the first step to design and develop the new hot corrosion resistant Ni-basestngle crystal superalloys by the d-electrons alloy design theory (or the New PHACOMP), acomprehensive evaluation of the phase stability of the modified widely used hot corrosionresistant IN 73SLC Ni-base superalloy [Ni-16Cr-9.5Al-4.0Ti-8.0Co-0.55Nb-0.06Zr-0.05B-0.47C-(0-3)Ta-(0-3)W-(0-3)Mo (at.-%) was conducted. The criti-cal conditions for suppressing the precipitation of brittle phase can be decribed by the elec-tronic parameters Mdt≤0.99 and Mdγ≤v0.93, which can be applied to the d-electrons alloydesign of hot corrosion resistant Ni-base superalloys with high Cr contents. They are themost important reference parameters for the alloy design practice. It was also proved that thetwo critical parameters Mdt and Mdγ are equivalent so that the Mdγ could be replaced byMdt, which will greatly simplify the alloy design process.

A study was conducted of the effects of refractory metals Ti, Ta and Nb on themicrostructures and properties of a hot corrosion resistant alloy system Ni-16Cr-9Al- 4Co-2W-1Mo-(0-4)Ti-(0-4)Nb, in at.-%, which was selected based on the d-elec-trons alloy design theory and some basic considerations of an alloying features of single crys-tal Ni-base superalloys. The contour lines of solidification reaction temperatures and eutectic(γ+γ′) volume fraction in the Ti-Ta-Nb compositional triangle were determined by DTA andimaging analyzer. Compared with the reference alloy IN738LC, in most of the compositionalranges studied, the designed alloys show very low amount of eutectic (γ+γ′), ≤0.4 v.-%, low-er solidification range, ≤65℃, and wider "heat treatment window", >100℃, which indi-cates that the alloys should have the promising microstructural stability, single crystalcastability and be easier for complete solution treatment. In wide compositional ranges, thedesigned alloys showed good hot corrosion resistance (mass loss less than 20 mg / cm~2 after24 h kept in moiten salt at 900℃). By summarizing the results, the promising alloy,compositional ranges with balanced propertise were determined for the final alloy design step,i.e., the single crystal growth and mechanical property characterization of the alloys selectedfrom the above regions.

TTT diagrams of the 0.27C-1Cr and 0.27C-1Cr-RE steels are establishedby means of dilatometric measurement for kinetic curves at different temperatures andmetallographic inspections, and the influence of RE on the TTT diagram is studied. The addi-tion of RE refines austenite grains, retards grain growth rate, raises Ac_3 and makes no changeto Ac_1. The incubation periods for proeutectoid ferrite and bainite are reduced, and the timefor complete transformation for pearlite and bainite are prolonged by the addition of RE. Thecomputation result are in comformity with the experimental ones.

A TEM study was made of the crystallography of the lath martensite formedin a Ultrahigh-strength steel 300M. It was found that the habit plane is close to {335}_A, theorientation relationship between the martensite and austenite is the G-T one which is 2.5°away from the K-S relationship, and the laths relate to each other by a relative rotation ofabout 60° about the normal to their common planes {110}_M. Although various orientationrelationships, including a near {112}_M twin one, could be formed between the lathsthemselves due to the rotations, a unique G-T orientation relationship was kept between thelath and austenite.

The embedded atom type potentials and static relaxation method combinedwith a steepest decent computational technique have been used to simulate the interaction be-tween the grain boundary and dislocations in Ni_3Al. The focus has been placed on the ener-getic features of the interaction, the distortion of grain boundary structural units and the dis-location core structures near the grain boundary. Implication has also been made on the re-sults for understanding of the mechanism responsible for boron-enhanced ductility.

During long-term holding in the sensitization zone, the diffusion layer, en-riched Cr_(23)C_6 particles, may be formed by the interface diffusion between steels 316L and 20.Thus, the mechanical properties of the composite wires would be reduced.

The cyclic hysteresis loops and their variation rules of base metal, weld metaland heat-affected zone for 16MnR pressure vessel steel were investigated by low-cycle fa-tigue tests. The definition of fatigue failure for welded joint was proposed, and the experimen-tal relations of cyclic hysteresis energy or total absorbed energy to failure vs the fatigue lifewere established. Finally, the effect of welding mechanical heterogeneity to fatigue damagewas discussed.

Thermodynamics of Cu-Ce-O, Cu-Ce-S and Cu-Ce-O-S solutions at1200℃ were studied by using solid electrolyte cell and chemical equilibrium method.The equilibrium constants of deoxidation, desulfurization and deoxysulfurization by Ce,the Gibbs standard free energies of the formation of Ce_2O_3, CeS, Ce_2O_2S in Cu-basesolution, activity interaction coefficients of S and Ce, temperature dependence of stand-ard free energy of solution of Ce in Cu and the self-interaction coefficients of Ce in liq-uid Cu have been obtained. The phase precipitation diagram for Cu-Ce-S-O systemhas been plotted. The steady thermodynamic condition of the existence of Ce_2O_3, CeSand Ce_2O_2S in liquid Cu has been determined.

An investigation was made of the structure and microhardness variation formelt-quenched Fe_(70)Cr_(18)Mo_2B_9Si_1 alloy, in comparison with Fe_(68.5)Cr_(18)Mo_2B_9Si_1Nb_(1.5), afterannealing under various temperatures. The effect of Nb on grain size of α-Fe matrix and thechemical composition, lattice parameters, nucleation and growth rate of M_2B andM_3B_2 borides phases have been analysed. It was observed that Nb may promote thenucleation of M_3B_2 and reduce the growth rate of M_2B and M_3B_2.

Average grain size of crystalline Ti powder may be yielded down to 12-13 nmafter 24 h milling. Its oxygen and nitrogen contents are very low. Relationship betweenhardness and grain size seems to be followed the usual Hall-Petch relationship.

The effect of composition, metallic and diluent content of the TiB_2-xAl com-posites upon the combustion temperature, propagating rate and volume change of samplesduring self-propagation high-temperature synthesis (SHS) has been studied. Different tem-peratures of ignitor may result in different ignition delay time, but the combustion tempera-ture and propagation rate of the SHS process are uninfluenced.