Microstructure evolution during preparation of in-situ TiB reinforced titanium matrix composites
来源期刊:中国有色金属学报(英文版)2003年第2期
论文作者:尚俊玲 李邦盛 郭景杰 傅恒志
文章页码:315 - 319
Key words:in-situ; titanium matrix composite; microstructure evolution
Abstract: By means of DTA, SHS quenching, XRD and SEM, the microstructure evolution during fabricating of TiB reinforced in-situ titanium matrix composite was studied. DTA result shows that there are two exothermic and one endothermic reaction during heating of Ti-B-Al system. The exothermic reactions correspond to the solid-solid diffusion reaction between Ti and Al, and the reaction of TiB formation respectively, and the endothermic reaction corresponds to melting of Al. The sample of SHS quenching presents four regions: unreacted region, heat-affected region, reacting region and product region. The microstructures of these regions reflect the process of microstructure evolution during preparation of in-situ TiB reinforced TMC. Ti, B, Al powders are in simple mechanical contact in the unreacted region; the sharp angles of original metal particles have become round and B diffuses into melted Al in the heat-affected region; TiB whiskers begin to appear and grow in the interior of reacting region. In product region, the TiB whiskers are uniform and fine. The result of XRD indicates that the reinforcements formed in product region are TiB whiskers. And the TiB is a hexagonal prism with a pyramidal head.