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The microstructure development of TC21 alloy after double α/β solution and aging heat treatment was investigated. Results show that primary α phase morphology is determined by the first solution treatment at the top of α/β portion. Varying the cooling rates can significantly influence the volume fraction of retained β phase and secondary α phase. Higher cooling rate results in greater retention of the β phase and transformation of the phase into secondary α phase upon aging. This higher amount of fine secondary α phase causes higher strength and lower toughness. Second α/β heat treatment temperature remarkably influences the heat treatment response of the microstructure. Higher heat treatment temperature keeps greater amounts of β with fine transformed α in the final microstructures. Lower α/β heat treatment temperature results in less responsive retained β during aging process. Aging treatment leads to decomposition of retained β phase, particularly in larger retained β regions that exhibit lower stability.

Hot deformation behavior of as-cast TC18 titanium alloy has been investigated by the Gleeble-3800 simulator in the temperature range 1000~1150 º C, the strain rate range 0.01~10 s-1 at the deformation degree of 70%. The deformation activation energy was evaluated, processing maps for hot working were established on the basis of variable efficiency in power dissipation with temperature and strain rate, and interpreted according to the microstructure observation. The optimum processing parameters of hot deformation in the range of this experiment were achieved by different variables of the hot processing map, which can be used as a reference for hot working of as-cast TC18 titanium alloy.

An antifouling surface is highly desirable for many biomedical applications. In this study, poly(vinyl chloride) (PVC) films were endowed with the improved properties of resisting nonspecific protein adsorption and platelet adhesion simply through being coated with a kind of mixed-charge zwitterionic polymer, poly(3-sulfopropyl methacrylate-methacrylatoethyl trimethyl ammonium chloride-glycidyl methacrylate) (PSTG), with random moieties of negatively charged 3-sulfopropyl methacrylate potassium, positively charged [2-(methacryloyloxy)-ethyl] trimethylammonium chloride, and glycidyl methacrylate. The PSTG-grafted PVC films were formed by the simple immersion of an amino-functionalized PVC film into a PSTG solution. A grafting density of 220.84 mg/cm 2 of PSTG4-grafted PVC film was successfully obtained. The PSTG4-grafted PVC film showed a lower contact angle (37.5 8) than the ungrafted PVC film (98.3 8). The in vitro protein adsorption results show that the bovine serum albumin adsorption amount decreased 6.72 mg/cm 2 in the case of the PSTG4-grafted PVC film, whereas that on the ungrafted PVC film was 28.54 mg/cm 2 . So, PSTG-grafted PVC films could be promising materials for medical devices.