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研究了部分重熔温度对触变成形Al-7Si-Mg合金显微组织和力学性能的影响。结果表明,重熔温度对粉末触变成形Al-7Si-Mg组织和力学性能有很大的影响。随着重熔温度升高,半固态坯料中的初生相颗粒形状、尺寸、体积含量的变化,以及随后触变挤压过程产生的缩松、液相偏聚等缺陷是导致力学性能变化的主要原因。当重熔温度为590℃、重熔时间为70 min、模具温度为300℃时,材料的抗拉强度、硬度(HV)和伸长率达到最大值,分别为262.7 MPa、84.48和10.9%。
The effect of partial remelting temperature on the microstructure and mechanical properties of thixoformed Al-7Si-Mg alloy was studied. The results show that the remelting temperature has a great influence on the microstructure and mechanical properties of the Al-7Si-Mg powder. With the increase of remelting temperature, the change of shape, size and volume content of the primary phase in the semi-solid billet, as well as the subsequent shrinkage and liquid segregation caused by thixotropic extrusion are the main reasons for the change of mechanical properties . When the remelting temperature is 590 ℃, the remelting time is 70 min and the mold temperature is 300 ℃, the tensile strength, hardness (HV) and elongation reach the maximum value of 262.7 MPa, 84.48 and 10.9% respectively.