挤压铸造SiC_w/L3复合材料的热挤压

Hot Extrusion of Squeeze-cast SiC_w/L3 Composites

研究了挤压铸造SiCw／L3复合材料不同温度下的热挤压行为。通过图像分析和性能测试对SiCw／L3复合材料热挤压棒中晶须状态和挤压棒的性能进行了分析和测定。结果表明，稳态挤压力随挤压温度的升高以及模具半角的减小而降低，高于固相线温度挤压造成挤压棒表面质量严重变坏，挤压温度、模具形状及挤压比对挤压棒中SiCw的取向和折断有较大的影响，热挤压可以大幅度提高SiCw／L3复合材料的强度和塑性。

In this paper, the hot-extrusion behavior of squeeze-cast SiCw/L3 composites was investigated under different temperature . The microstructure with emphasis on the breakage and alignment and the properties of as-extruded SiC2/L3 composites were examined. The results show that the steady state extrusion pressure decreases with increasingtemperature and reducing die half angle. Extrusion above solidus temperature causes a severe damage to the surface appearance of extruded bare. The extrusion temperature and shape of dies as well as extrusion ratio are main factors affectingthe orientation and breakage of SiC whiskers. It is also demonstrated that the shrength and plasticity of SiCw/L3 composites can be greatly increased by hot extrusion.