【摘要】 将纯钛粉和B4C粉按一定比例混合均匀后,通过反应热压方法原位合成制备了TiB晶须和TiC颗粒增强体积分数为3%的钛基复合材料,并在950℃以16:1的挤压比对复合材料进行了高温热挤压变形.采用X射线衍射仪和扫描电镜分别研究了原位生成复合材料的相结构和微观组织,并在700℃以不同应变速率对钛基复合材料进行了高温拉伸变形.研究表明:纯钛和B4C在1200℃真空热压原位合成产生两种不同形状的增强体,即短纤维状TiB晶须和等轴状的TiC颗粒;应变速率为5.95×10-4、1.19×10-3s-1和0.89×10-2s-1时,(TiBw+TiCp)/Ti复合材料都表现出超塑性,延伸率分别为205.43%、148.3%和112.85%;700℃变形时(TiBw+TiCp)/Ti复合材料的应变速率敏感指数为0.45.更多还原

【Abstract】 (TiBw+TiCp)/Ti composites,with reinforcements volume fraction of 3%,was fabricated by hot pressing reaction between Ti powders and B₄C powders.The composites were hot extruded at extrusion ratio of 16:1 at 950 ℃.Microstructure of the composites before and after extrusion was investigated by means of XRD and SEM.The tensile tests of the composites were conducted at 700 ℃ with different strain rates.The results of SEM and TEM show that TiB whisker are roll-like and TiC particles generally exhibit an equiaxed shape.The high strain rate superplasticity were obtained in the（TiBw+TiCp）/Ti composites with the strain rates of 5.95×10^-4,1.19×10^-3 s^-1 and 0.89×10^-2 s^-1 ,the elongations were 205.43%,148.3% and 112.85%,respectively.The strain rate sensitivity parameter m of the composite is about 0.45.更多还原