(哈尔滨工业大学材料科学与工程学院,哈尔滨 150001)
摘 要: 研究了挤压比和挤压温度对挤压铸造SiCw/L3复合材料组织和性能的影响。结果表明,当挤压温度升高时,晶须沿挤压方向定向排列程度基本未变,而晶须的折断程度则减弱,导致复合材料的抗拉强度提高;当挤压比增大时,晶须沿挤压方向定向排列程度增大,晶须的折断程度也增大,这两个决定强度的相反过程造成了复合材料的抗拉强度在挤压比为18∶1时出现最大值。用修正的混合法则预测挤压态复合材料强度时,必须增大基体对强度贡献部分的系数c*。
关键字: SiCw/Al复合材料 热挤压 组织 抗拉强度
(School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, P R China)
Abstract:Effects of extrusion ratio and temperature on the microstructure and properties of 15%SiCw/L3 composites have been investigated. Results showed that , with an increase of extrusion temperature the degree of whiskers' directional alignment along the extrusion direction nearly remains unchanged, but the breakage degree of whiskers decreases, which results in an increase of tensile strength. And with an increase of extrusion ratio the degree of whiskers' directional alignment along the extrusion direction increases and the breakage degree of whiskers increases too, which together result in a maximum value of tensile strength at an extrusion ratio of 18∶1. The coefficient c* representing the contribution of matrix to the strength, ought to be increased when the modified Rule of Mixture (ROM) is used to predict the strength of extruded composites.
Key words: SiCw/Al composite; hot extrusion; tensile strength