Effect of Si Content on Mechanical Properties of Ti-Si-N Ternary Alloys Prepared by Spark Plasma Sintering

Abstract

In the present work, the strengthen mechanism of Ti-Si-N ternary alloys prepared by Spark Plasma Sintering (SPS) was investigated. Ti, Si and TiN substrate powders were prepared in order to obtain nominal composition of Ti-0.35Si-1TiN and Ti-0.7Si-1TiN (wt %). Homogenization was performed before extrusion. Microstructure and phase identification were analyzed by Optical Microscope (OM) and X-ray diffraction (XRD). In order to evaluate the mechanical properties of extruded specimens, micro hardness test and tensile test were carried out. The XRD results show that no Si and TiN particles are remained after SPS and no any reaction caused of intermetallic compound during heat treatment and extrusion processes. It is found that the abnormal phase with high N-content was observed in matrix phase. It is also obvious that increasing Si from 0.35Si to 0.7Si (wt %) can increase yield stress and ultimate tensile stress from 1006±15 to 1092±5 MPa and 1089±10 to 1170±10 MPa, respectively. Hence, the strengthening mechanism by addition Si content into Ti-1TiN (wt %) is only solid solution mechanism.