挤压温度对B_4C/Al-Si复合材料组织和性能的影响

Effect of Extrusion Temperature on Microstructure and Properties of B_4C/Al-Si Composite

以Al-Si合金粉末和B4C粉末为原料,采用粉末热挤压法制备了B4C/Al-Si复合材料,研究了挤压温度对该复合材料组织和性能的影响。结果表明:挤压温度为350～500℃时,B4C在Al-Si基体中均匀分布,无团聚现象;挤压温度为450℃及以上时,挤压组织达到致密化;随着挤压温度的升高,该复合材料的抗拉强度、屈服强度和屈强比降低,伸长率增大;挤压温度超过450℃时,基体中的Si相数量明显减少,晶粒显著增大;拉伸断裂是微孔聚集型韧性断裂,韧窝是该复合材料拉伸断口的主要特征。

B4C/A1-Si composite was prepared by hot extrusion process using A1-Si alloy powder and B4C powder as raw material. The effect of extrusion temperature on the microstructure and properties of the composite was studied. The results show that B4C distributes uniformly in A1-Si matrix, and no particle agglomeration is found. The composite is densified when the extrusion temperature reaches 450℃. With the increase of extrusion temperature, the tensile strength, yield strength and yield ratio decrease while the elongation increases. When the extrusion temperature exceeds 450℃, the number of silicon crystal decreases while the particle size obviously increases. The fracture modes of the composite are micro-void coalescence ductile rupture, and the dimple is the main characteristic of tough fracture.