不同压力下挤压铸造铝铜合金的组织与性能

采用挤压铸造工艺制备出一种新开发的、高强韧铝铜合金.T5热处理状态下其抗拉强度达到433 MPa,伸长率为14%.通过对该合金力学性能及其显微组织的研究表明,铸态和经T5热处理的抗拉强度和伸长率均随压力的增加而增大,在压力为50MPa时达到最大值,但在铸态下,未加压力的铸造合金其硬度高于挤压铸造的合金硬度.随挤压力增加,晶粒明显细化,二次枝晶增加,枝晶间距减小.

Microstructure and Properties of Squeeze Cast Al-Cu Alloy with Different Applied Pressure

Squeeze casting process was used to produce a newly developed high strength and high toughness Al-Cu alloy. The alloy in T5 heat-treated condition is 433 MPa in ultimate tensile strength and 14% in elongation. Microstructure and mechanical property of the alloy were examined in the as-cast and T5 heat-treated conditions to determine the effect of the squeeze pressure. Results show that the ultimate tensile strength, elongation and density of the as-cast and T5 heat-treated castings increase with the applied pressure and reached a maximum at a pressure of 50 MPa, respectively, but the hardness of the alloy without squeeze pressure is higher than that of those squeeze casts. The grain size and the dendrite arm spacing decrease and more dendrites appear with the increase of applied pressure.