Preparation and Grain Growth of Fine-Grained Sintered Molybdenum Alloy Dispersed with Titanium Carbide.

Fine-grained sintered molybdenum alloy dispersed with 1.6mol% (1.0mass%) TiC was prepared by mechanical alloying and hot isostatic pressing. The mixture of fine molybdenum powder with grains measuring 20nm in diameter and TiC-particles, prepared by mechanical alloying, was sintered at 1570K for 10.8ks under 147MPa. Density of the sintered alloy was 10.1Mg/m3 (99.5% relative density); grain size of the molybdenum and the particle size of TiC in the sintered alloy were 0.4μm and below 0.2μm, respectively.Grain growth of the alloy was measured to estimate stability of the fine-grained microstructure at high temperatures. Fine grains measuring 2μm in diameter were remained after heating at 207OK for 3.6ks. (Ti, Mo)C1-x was formed at the interface of the molybdenum and TiC-particles, and grains of molybdenum grew to 4μm in diameter after heating at 2270K for 3.6ks. After heating at 247OK, many voids and traces of liquid phase were observed at the grain boundary.