The as-cast Mg-alloys ZK60 and ZK60+1.0Cu (mass fraction, %) were fabricated by permanent mold casting, then, the homogenization heat treatment and two-step extrusion-shearing process were performed for the alloys. The microstructure, phase constitution and mechanical properties of the extrusion-shearing alloys were characterized by means of OM, SEM, EDS, XRD, EBSD, TEM and tensile-compression test at ambient temperature. Results indicated that the ternary MgZnCu phase could be observed in the interiors of α-Mg matrix of the alloy with addition of 1.0Cu. The quantitatively measured average grain size of α-Mg matrix of ZK60+1.0Cu alloy in the forming area was 1.56 μm, which was much less than that of ZK60 alloy (4.68 μm). Furthermore, the sub-grains of 300±45 nm in size were observed around the MgZnCu phase. The ZK60+1.0Cu alloy in the forming area possessed weaker {0001} basal texture while the angle between basal pole and extrusion direction (ED) was changed as compared with ZK60 alloy, resulted in the existence of more dynamic recrystallization (DRX) grains, which was beneficial to {0001}<11\bar{\mathrm{2}}0> basal slip. The tensile and compressive strength of ZK60+1.0Cu alloy in the forming area was obviously higher than that of ZK60 alloy owing to the grain boundary strengthening, and the occurrence of micro-voids near or within the fractured MgZnCu phase mainly accounted for the decrease of tensile elongation.

The intermediate temperature creep behavior and microstructure of samples misaligned 15^o from <001> crystallographic axis for a nickel-based single crystal superalloy were systematically investigated. The results show that the creep life of samples with orientation close to the <001>-<101> symmetry boundary is the longest, while the creep life of samples with orientation close to the <001>-<111> symmetry boundary is the shortest. Although the misorientation angles of the three samples deviated from <001> were all about 15^o, their microstructure was obviously different. The deformation of the samples close to the <001>-<101> was mainly controlled by the sliding system of {111}<110>, while the deformation of the samples close to the <001>-<111> was mainly controlled by the sliding system of {111}<112>.

Corrosion behavior of DP600 dual phase steel in two different accelerated test environments, namely neutral salt spray (NSS) test and cyclic salt spray corrosion test (CCT) was comparatively assessed by means of SEM, EDS, XRD and EIS. Results show that the corrosion mass loss of the steel in the two environments was gradually increased, and the amount of mass loss in CCT was higher than in NSS test. At the same time, there was no significant difference in the initial corrosion rate, however the maximum corrosion rate reached 1.89 g·m^-2·h^-1 (NSS) and 2.72 g·m^-2·h^-1(CCT) at 480 h respectively. The rust layer of the steel after the NSS test composed of Fe₃O₄, α-FeOOH, γ-FeOOH, δ-FeOOH and α-Fe₂O₃, besides, there existed significant amount of β-FeOOH for the rust layer of the steel after CCT test. The rust layer of the steel after CCT test is thicker than that after NSS test, whilst the thickness increases faster for the former rust layer. The EIS results show that the resistance of sample solution and corrosion product film are gradually increased in both accelerated tests, furthermore the charge transfer resistance decreased first and then increased. The corrosion rate of the steel during NSS test and CCT test can be described as: ΔD_1-1=0.7349t^{\mathrm{0.1522}} and ΔD_2-1=0.3511t^{\mathrm{0.3313}} for the early stage (t≤480 h), while ΔD_1-2=14.6239t^{-\mathrm{0.3236}} and ΔD_2-2=6.8542t^{-\mathrm{0.157}} for the later stage (t>480 h) respectively.

The thermal mechanical control processing (TMCP) for hot-rolling of P91 seamless steel pipe was designed based on the features of PQF process and the relevant research results of its dynamic phase transition regularities. Then the hot deformation processes for piercing, continuous rolling and sizing of P91 pipe were simulated by means of Gleeble-1500D thermal-mechanical simulator. Whilst the microstructural evolution of P91 pipe during TMCP was assessed by SEM and TEM, and the refinement and strengthening of deformed austenite and its martensitic transformation behavior were also investigated. The results show that the large deformation at higher temperature with true strain of 1.8 during piercing and continuous rolling may benefit the recrystallization and the refinement of deformed austenite grains, while the accumulation of sizing deformation at 990℃ may strengthen the deformed austenite and induce the martensitic transformation during the TMCP of P91 pipe. Martensite laths with a thickness of 0.1~0.5 μm were obtained via proper controlled cooling of 1℃/s. Fine twins of 2~20 nm and high density dislocations were found in Martensite laths. The nanoscale precipitates of (Cr,Fe,Mo)₂₃C₆ with a size of about 20 nm×100 nm were found between the laths of the martensite. This structure characteristic is the imprint of the TMCP effect of fine grain strengthening, precipitation strengthening and phasetransformation strengthening, which can greatly improve the mechanical properties of P91 pipe. The feasibility of TMCP for P91 pipe was verified by the actual production.

Hot compression tests of as-forged Ti-alloy TB6 were conducted via thermecmaster-Z hot simulation test machine through rapid heating the alloy up to the temperature range for the presence of β-phase and then compression tests by strain rates of 0.001~1 s^-1 at temperatures in the range of 825~1100℃, while the dynamic recrystallization (DRX) volume fraction were acquired by processing the collected rheological data during compression deformation with work hardening rate approach, then the kinetics of DRX of the alloy deformed at β-phase temperature was studied. The results show that the stress increases with the decrease of deformation temperature or the increase of strain rate, and the stress-strain curves present the type of DRX. With the decrease of strain rate and the increase of deformation temperature, the DRX volume fraction and the grain size of dynamic recrystallization increase. The DRX grain coarsening is observed for the alloy deformed at temperatures above 950℃ and strain rates below 0.001 s^-1. The DRX kinetics curves possess three typical stages: slow increase-fast increase-slow increase, showing a typical "S" type characteristic. Furthermore, the strain corresponding to the presence of 50% DRX volume fraction was determined and the relevant DRX kinetics model of TB6 Ti-alloy is established.

The mechanical properties of a novel heterogeneous cold-rolled medium Mn steel were investigated by means of mechanical testers, in situ EBSD (electron back-scattered diffraction) and SDTEM (spherical differential transmission electron microscope). The results show that the sample annealed at 680°C consists of multiple microstructure of austenites (granular shape, blocky shape, and lath-like shape) and fine ferrite grains. The heterogeneous steel has ultimate tensile strength of 1.27 GPa, total elongation of 54.5% and product of strength and elongation of 69.3 GPa·%. During tensile deformation the granular-shape austenite with a low C/Mn content preferentially transforms into martensite ahead of the blocky-shape and lath-like austenite with high C/Mn content, and the multi-type microstructure of austenite with various stability lead to a continuous TRIP effect in a large strain region, which is responsible for the excellent properties of the heterogeneous medium Mn steel. In addition, austenite grain boundaries or austenite/ferrite interfaces are the preferred nucleation zone of martensite during deformation. The effect of Mn/C content on austenite stability readily overrides those of grain size.

C/C composites with different carbon matrix structures were prepared by CVI(chemical vapor infiltration) +PIC(resin precursor impregnation cracking) process using 2D carbon fiber needle-punched preforms as reinforcement and then were heat-treated at different temperatures. The effect of PyC (pyrolysis carbon)/ReC (resin carbon) ratio and degree of graphitization on the electrical resistivity of the composites was investigated. The results show that the electrical resistivity of the C/C composites of low density remains basically unchanged in a range of 27.3×10^-6~28.0×10^-6 Ω·m with the increase of PyC/ReC, which can be mainly attributed to the opposite effect of the increase of lattice size and structural integrity of graphite microcrystals and the increase of porosity of the composites. However, the electrical resistivity of C/C composites of high density decreases from 24.9×10^-6 Ω·m to 20.5×10^-6 Ω·m with the increase of PyC/ReC ratio. Because the slight increase of the porosity has a small contribution on the difference of electrical resistivity by hindering the effective carrier transfer in the conductive network for the C/C composites of low porosity. The graphitization degree of C/C composites increases and the electrical resistivity decreases with the heat treatment temperature increased from 1800℃ to 2500℃, which can be mainly attributed to the increase of carrier concentration and the weakening of grain boundary scattering.

Al nano-particle modified organosilicone coatings were prepared on stainless steel 304SS. The curing properties at room temperatures, high temperature oxidation behavior at 650oC in air and electrochemical corrosion behavior in 3.5% NaCl solution of the coatings were investigated. The silicone coatings can be cured at room temperatures in 24 h only when the mass ratio of polyurethane over silicone is equal to or higher than 1:3. The as-prepared silicone coatings were smooth and free of cracks. The high temperature oxidation resistance of 304SS was greatly improved by applying the modified silicone coating. After oxidized for 1028 h at 650oC in air, the oxide scale on the coated 304SS was hardly discernable, while the coatings remained intact and free of cracks. Besides, after high temperature oxidation, the electrochemical corrosion resistance of the 304SS coated with modified silicone coating in NaCl solution was greatly improved, too. Without the protection of the coating, the impedance at low frequency of oxidized 304SS without coating was as low as 3.2 Ω·cm², while that of the sample with coating was as high as 1.1×10⁵ Ω·cm².