模具温度对Si_p/ZA27复合材料组织及性能的影响

Effects of Mould Temperature on Microstructure and Tensile Properties of in situ Thixoformed Si_p/ZA27 Composite

研究了模具温度对触变成形Sip/ZA27复合材料组织及力学性能的影响。结果表明,随着模具温度升高,锭料的凝固速率变慢,初生α-Al颗粒尺寸和体积分数增大;而且初生α-Al颗粒中Zn元素的含量增加;此外,Si颗粒的团聚倾向变得严重。通过对试样的力学性能进行比较可知,最佳的模具温度为200℃,此时的抗拉强度和伸长率分别达到382 MPa和1.17%。而且随着模具温度的增加,断裂机制发生转变。

Effects of mould temperature on microstructure and tensile properties of in situ thixoformed Sip/ZA27 composites were investigated. The results indicate that with the mould temperature increases, the solidification rate of ingot is decreased, and the size and fraction of the primary α-Al particles are increased. Moreover, Zn conent in the primary particles is increased. In addition, the aggregation tendency of Si particles tends to become serious. Based on tensile properties testing, the optimal mould temperature is 200 ℃, where the tensile strength and elongation reach up to 382 MPa and 1.17% ,respectively. Moreover, the fracture mode of the thixoformed composites is transformed with the mould temperature increase.