挤压铸造半固态A356铝合金的组织与力学性能

采用低温铸造方法制备A356铝合金半固态坯料.在200 t立式油压机上用挤压铸造方法将A356铝合金半固态浆料挤压成件.研究挤压铸造件的微观组织、力学性能,并与液态挤压铸造件进行比较.结果表明,A356铝合金半固态挤压铸造件组织由球形及椭圆形α-Al晶粒和α+Si共晶成分组成,且制件充型完整、无宏观缩孔、组织致密.在比压48.7 MPa,浇注温度575℃,保压时间3s条件下成形的半固态挤压铸造件的抗拉强度、屈服强度、伸长率分别达到278 MPa、225 MPa、13.2％,相比于在比压48.7 MPa,保压时间3s,710℃液态挤压铸造件性能分别提高了8.6％、8.2％、24.5％.A356铝合金半固态挤压铸造成形件具有较高的综合力学性能.

Microstructure and Mechanical Properties of Squeeze Casting A356 Aluminum Alloy in Semi-solid State

The semi-solid A356 aluminum alloy billets were prepared by low temperature casting.The semi-solid alloy was made into parts by squeeze casting in 200 t vertical hydraulic press.The microstructure and mechanical properties of the parts were investigated and compared with that of parts forged in liquid.The results show that the microstructure of the parts of squeeze casting semi-solid A356 aluminum alloy is composed of spherical and ellipse α-Al and α+Si eutectic phase,and the parts fill smoothly and posses compact structure and no macroshrinkage.Tensile strength,yield strength and elongation of the samples of semi-solid squeeze casting in the condition of stress 48.7 MPa,pouring temperature 575 ℃ and holding time 3s can reach 278 MPa,225 MPa,13.2%,respectively,which is improved by 8.6%,8.2%,24.5%,respectively,compared with that of liquid squeeze casting in the condition of stress 48.7 MPa,pouring temperature 710 ℃ and holding time 3 s.The parts of semi-solid squeeze casting A356 aluminum alloy have better comprehensive mechanical properties.