Papers by Author: Ai Bin Li

Abstract: (α+β)/β phase transformation temperature of a TC11 titanium alloy was confirmed to be 1035°C, which was obtained by three methods including the calculation method, differential scanning calorimetry and metallographic techniques. Based on this result, annealing treatments below and above the (α+β)/β phase transformation temperature were carried out, and the microstructure of the TC11 alloys before and after annealing treatment was analyzed by SEM. The result showed that conventional annealing below 1035°C does not change the Widmanstaten structure of TC11 alloy, though the thickness of α lamellar structure becomes thicker with increasing the annealing temperature. The microstructure of the TC11 alloy treated by annealing above the α+β/β transformation temperature is non-uniform because of the different forming temperature and growing duration of α phase in the TC11 alloy.

Abstract: The effect of temperature on strain softening behavior of composites with small misaligned whiskers is investigated. The results show that the temperature affects the matrix and whisker mechanical behavior and corresponding composite deformation behavior. With increasing temperature, the whisker rotation angle increases, but their breakage decreases. Meanwhile elevating temperature not only reduces the matrix flow stress and work hardening rate, but also decreases load transfer from the matrix to the whiskers and stress induced by the whisker rotation and breakage.It is found that during hot compression, strain softening behavior of composites decreases as temperature increases.

Abstract: By incorporating the Taylor-based nonlocal theory of plasticity, the finite element method (FEM) is applied to investigate the effect of particle size on the deformation behavior of the metal matrix composites. In the simulation, the two-dimensional plane strain and random distribution multi-particles model are used. It is shown that, at a fixed particle volume fraction, there is a close relationship between the particle size and the deformation behavior of the composites. The yield strength and plastic work hardening rate of the composites increase with decreasing particle size. The predicted stress-strain behaviors of the composites are qualitative agreement with the experimental results.