凝固速率对Mg_2Si/Al复合材料组织和力学性能的影响

Effect of solidification rate on microstructure and mechanical properties of Mg_2Si/Al composites

在不同凝固速率条件下制备了原位内生Mg_2Si和Si颗粒增强的Mg_2Si/Al复合材料,研究了凝固速率对其组织和力学性能的影响。结果表明,随着凝固速率增加,初生Mg_2Si和初生Si的颗粒数量增加,多边形初生Mg_2Si趋向转变为四边形形貌,初生Si形貌则无明显变化。随着凝固速率的加快,前者的平均尺寸由30μm变为6μm,后者的平均尺寸由71μm变为21μm。性能测试显示,Mg_2Si/Al复合材料的硬度,抗拉强度和伸长率也都随着凝固速率的提高而有所增长。最佳凝固速率为460℃/s,此时复合材料的硬度、抗拉强度和伸长率分别为169 HV0.2、221 MPa和1.63%。

Mg2Si/Al composites reinforced by in-situ Mg2Si and Si particles were fabricated at different solidification rates. The effect of solidification rate both on microstructure and mechanical properties was investigated. The results show that,with increasing the solidification rate,there are increase in the particle numbers of primary Mg2Si and primary Si. The polygonal primary Mg2Si transits to cuboid,while the morphologies of primary Si has no obvious change. With increasing the solidification rate,the average size of the former changes from 30 μm to 6 μm,while that of the latter changes from 71 μm to 21 μm. The property tests show that,the hardness,the ultimate tensile strength and the elongation of Mg2Si/Al composite both increase with the increasing of the solidification rate. The optimum solidification rate is 460 ℃/s with a hardness of 169 HV0. 2,a ultimate tensile strength of 221 MPa and an elongation of 1. 63% of the composites.