Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : September 03, 2017 - September 06, 2017
Thoriated tungsten alloy (ThO2-W) has been used as cathode material in discharge lamp and for TIG welding rod because of its excellent thermoelectric emission properties. However, ThO2 is one of radioactive substances, therefore development of thoria free tungsten is desired. In this study, hafnium carbide (HfC) was used as an alternate material of ThO2. The material used, HfC-W alloys was produced with spark plasma sintering (SPS) and tensile strength of the alloy at elevated temperature was evaluated. Tensile strength of HfC-W sintered by SPS decreased with increasing testing temperature. Tensile strengths at 1300 and 1500°C in HfC-W sintered by SPS were lower that in the same alloy but sintered by conventional electrical sintering technique. According to microstructure observation by SEM-EDS in the materials used, coarse aggregate of HfC were observed in HfC-W sintered by SPS, while small HfC particles were distributed in the matrix for HfC-W sintered by electrical sintering. It is considered that difference in dispersion state of HfC particles possibly affects tensile strength of the materials used.
