Densification dynamics and microstructure evolution behaviors of spark plasma sintering of titanium powders

Spark Plasma Sintering (SPS) is characterized by a significant short-term rapid densification. However, the densification kinetics, structure and performance characteristics of this process still need further investigation. Since titanium has a series of excellent physical and chemical properties, it is widely used in biomedical, electronics and other target areas. In the present paper, titanium was used as a typical material. A set of titanium samples were prepared under the pressure of 20 MPa and in a temperature range of 600~875 for the purpose of studying the dynamic behavior of its rapid densification. The results show that the samples densified at a low temperature (600~725) have a densification index of 1.5 due to the pure diffusion combined with high-temperature creep. Index of samples densified at high temperature (800~875) is 2, indicating its densification mechanism of high temperature creep. The effect of temperature on microstructure, porosity and mechanical properties was also studied. As the increase of temperature the Vickers hardness of the sample increases gradually. The higher the temperature goes, the faster the heating rising rate, the better mechanical properties the sample obtain. ©, 2015, Central South University. All right reserved.