压射速度对压铸Al-20%Si合金组织与性能的影响

Influence of Injection Speed on Microstructure and Mechanical Property of Die Casting Al-20% Si Alloy

基于液态压铸技术,研究了压射速度对Al-20%Si合金显微组织与性能的影响,同时利用扫描电子显微镜(SEM)对其拉伸断口形貌进行分析。结果表明:随着压射速度的增大,试样的抗拉强度、伸长率和冲击韧度先增大而后减小,硬度总的趋势是降低的,但硬度值变化不大。合金的断裂方式为解理断裂。在实验条件下,增压压力16MPa、模具温度150℃、浇注温度720℃、压射速度2.5m/s时,压铸Al-20%Si合金的力学性能较优,其力学性能可以达到:σb=280MPa、δ5=4.83%、Ak=25.56 J/cm2、硬度=80.6HBS。

The influence of injection speed on the microstructure and mechanical properties of die casting Al-20%Si aluminum alloy was investigated by liquid die casting technology,and the fracture surface was analyzed by scanning electron microscopy.The results indicate that with the increase of the injection speed,the tensile strength,percentage elongation and impact toughness firstly increases and then decreases,while the hardness decreases;the fracture mode of the material is cleavage fracture.Under the experiment conditions,at the injection pressure of 16 MPa,die temperature of 150 ℃,pouring temperature of 720 ℃ and injection speed of 2.5 m/s,the mechanical properties of Al-20%Si alloy is better,σb=280 MPa,δ5=4.83%,Ak=25.56 J/cm2 and H=80.6 HBS.