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研究了等温处理工艺对触变压铸Al-30Si合金(加入1wt%的磷盐变质处理)组织和力学性能的影响。结果表明,触变压铸组织中,初生硅的形貌较为圆整,针状的共晶硅消失。在高压下快速冷却,αAl来不及长大,颗粒大小分布是弥散的;在固相率较高共晶组织未全部熔化时,组织中的αAl以固相保留,形态为球状或近球状。在620℃,抗拉强度随保温时间的延长而增加。保温时间从80min增加到120min时抗拉强度从206MPa增大到220MPa,布氏硬度从92HB减小到84HB;在同一保温时间(100min)时,保温温度升高,抗拉强度先增大后减小,最大值为213MPa(620℃)。保温时间的增加或保温温度的升高,布氏硬度都呈现出减小的趋势。
The effects of isothermal treatment on the microstructure and mechanical properties of thixotrope-cast Al-30Si alloy (adding 1wt% phosphorus salt) were studied. The results show that the morphology of primary silicon is more rounded and the acicular eutectic silicon disappears in the thixotropic die-casting structure. After rapid cooling under high pressure, αAl is too late to grow up, and the particle size distribution is diffusive. When the eutectic microstructure with high solid fraction is not completely melted, the αAl in the microstructure retains in the form of solid or spherical shape. At 620 ℃, the tensile strength increases with the holding time. When the holding time increases from 80min to 120min, the tensile strength increases from 206MPa to 220MPa and the Brinell hardness decreases from 92HB to 84HB. At the same holding time (100min), the holding temperature increases and the tensile strength first increases and then decreases Small, the maximum value of 213MPa (620 ℃). When the holding time increases or the holding temperature increases, the Brinell hardness shows a decreasing trend.