淬火速率对汽车用高强铝合金性能的影响

采用力学性能测试、电导率测试和透射电子显微镜研究了淬火速率对汽车用高强铝合金性能的影响。结果表明：淬火速率从960℃/s降低到1.8℃/s，电导率提高了5.7% IACS，硬度的下降率为40%，抗拉强度和屈服强度的下降率分别为24.2%和56.9%，硬度和强度与淬火速率的对数呈线性关系。随着淬火速率的降低，淬火析出相的尺寸和面积分数显著增大，导致性能下降。淬火速率为1.8℃/s时，淬火析出相的平均尺寸为465.6 nm×158.2 nm，析出相的面积分数为42.1%。

Effect of Quenching Rate on Properties of Automotive High Strength Al-alloy

The effect of quenching rate on the microstructure and properties of automotive high-strength Al-alloys were investigated by mechanical property testing, electrical conductivity measurement and transmission electron microscopy. The results show that as the quenching rate decreased from 960^oC/s to 1.8^oC/s, the electrical conductivity increased by 5.7% IACS, the hardness reduction rate is 40%, and the reduction rates of tensile strength and yield strength are 24.2% and 56.9%, respectively. The hardness and strength are linearly related to the logarithm of quenching rate. With the decrease of quenching rate, the size and area fraction of quenching precipitates increase significantly, resulting in the decrease of performance. When the quenching rate is 1.8^oC/s, the average size and the area fraction of the quenching precipitate are 465.6 nm×158.2 nm and 42.1%, respectively.