一种同步提高压铸Al-Si-Fe合金导热性和强塑性的新方法

A New Method for Synchronously Improving Thermal Conductivity, Strength and Plasticity of Al-Si-Fe Alloy

目的同步提高压铸Al-Si-Fe合金(Y7)的导热性和强塑性。方法引入Al_3BC粒子以实现材料改性,先研究重力铸造性能,再应用至高压压铸。结果重力铸造条件下,引入Al_3BC粒子后测得试样的平均抗拉强度(UTS)、屈服强度(YS)、伸长率(EL)、热导率(k)分别为201.74 MPa, 106.13 MPa, 11.49%, 195.2 W/(m·K),相比于未引入粒子的情况分别提高了8.4%, 9.6%, 10.8%, 2.6%。应用在压铸件上也获得了较为理想的力学性能(UTS:295 MPa;YS:220 MPa;EL:3.5%)和热导率(k=146.72 W/(m·K))。结论纳米Al_3BC粒子能够实现Y7铝合金导热性和强塑性的同步改进,是基于Al_3BC粒子与α-Al基体较低的错配度以保证良好的导热性;以及弥散分布的粒子抑制共晶Si相的生长,从而达到细晶强化、弥散强化的效果。

This work aims to improve the thermal conductivity and strength and plasticity of Al-Si-Fe high pressure die casting(HPDC) aluminum alloy at the same time. Al3BC particles(Al3BCp) were used under gravity casting(named Y7(GC)) and then used in high pressure die casting(named Y7(HPDC)). After adding Al3BCp, the mean ultimate tensile strength(UTS), yield strength(YS), elongation(EL) and thermal conductivity(k) of Y7(GC) was 201.74 MPa, 106.13 MPa, 11.49% and 195.2 W/(m·K) respectively, which increased 8.4%, 9.6%, 10.8% and 2.6% separately by contrasting with the alloys without adding particles. When Al3BCp applied to die casting, Y7(HPDC) also showed more excellent tensile properties(UTS: 295 MPa; YS: 220 MPa; EL: 3.5%) and thermal conductivity(146.72 W/(m·K)). The innovative method is based on the smaller mismatch between particles and α-Al to ensure a good thermal conductivity and Al3BCp restrain the growth of eutectic silicon and particles dispersive distribution which play a role of fine grain strengthening and distribution strengthening.