挤压铸造比压对A357合金组织及性能的影响

Effects of the Specific Pressure in Squeeze Casting Processing on Mechanical Property and Microstructure of A357 Aluminum Alloy

采用挤压铸造试验模具,研究了挤压铸造工艺对A357合金组织及力学性能的影响。研究表明,当挤压比达到50 MPa时,可有效消除铸件铸造缺陷;达到90 MPa时,A357合金铸件密度显著提高。当挤压比压达到150 MPa时,α晶显著细化,二次枝晶间距也明显缩短,合金综合力学性能显著提高,在该工艺条件下,A357合金铸态性能可达到:Rm≥266 MPa,A≥7.5%,HB≥88;经T6处理后性能可达到:Rm≥373 MPa,A≥10.5%,HB≥121。本项目研究结果可为我国开展汽车底盘安保铝合金铸件研制提供借鉴。

Study on the effects of the pressure in squeeze casting on mechanical property and microstructure of A357 aluminum alloy with the experiment mould was carried out in this paper. The results show that the casting defect is eliminated when the specific pressure is 50 MPa. The density of the casting is raised when the specific pressure is 90 MPa. The oL（Al） crystal is thinner and the SDAS is shorter when the specific pressure is 150 MPa. And the mechanical property is obviously raised under the same process condition. The mechanical property of A357 alloy can meet： Rm≥266 MPa, A ≥7.5%, HB ≥88（F）, and the properties of alloy with T6 heat-treatment can meet： Rm≥ 373 MPa, A ≥ 10.5%, HB ≥ 121 （T6）. The research results can provide reference for the production of domestic automobile chassis security aluminum alloy castings.