A356铝合金的变质处理

Inoculation of A356 Aluminum Alloy

汽车轮毂通常采用A356铝合金制作。变质处理可减少356合金轮毂的铸造缺陷,从而提高其力学性性能。为此,分别采用0.015%、0.02%、0.03%和0.04%Sr(质量分数)对A356合金进行了变质处理,检测了合金的显微组织和力学性性能,并与未经变质处理的合金进行了比较。结果表明:随着锶含量增加至0.03%,合金中初生α-Al从不规则的枝晶转变为细小的等轴晶,共晶硅呈细小颗粒状和蠕虫状;合金的抗拉强度从未变质合金的169 MPa提高到了198 MPa,断后伸长率则从4.5%增加到了7.8%。

Automobile hub is commonly made of A356 aluminum alloy.Inoculation may lessen casting defects of A356 alloy hub thus improve its mechanical properties.For this reason the A356 alloy was modified by addition of0.015,0.02,0.03,and 0.04% Sr(by mass),respectively.Subsequently,microstructure and mechanical properties of the alloy were detected,and compaired with those of the alloy not modified.The results showed that as strontium content increased up to 0.03%,the primary α-Al changed from irregular dendrite to fine equiaxed crystals,and the eutectic silicon appeared as fine particles and worms.In addition,tensile strength and elongation were accordingly 169 MPa and 4.5% for the alloy without strontium and 198 MPa and 7.8% for the alloy with0.03%Sr.