Mn元素对不同淬火工艺下Al-Mg-Si合金组织与力学性能的影响

Effects of Mn Addition on the Microstructures and Mechanical Property of Al-Mg-Si Alloy with Different Quenching Process

摘要: 本文采用拉伸性能、光学金相、扫描电镜及透射电镜等手段研究了Mn元素对不同淬火工艺下Al-Mg-Si合金组织性能的影响。结果表明，Mn元素的添加细化了基体晶粒和第二相粒子尺寸，提高了合金断后伸长率；然而，微量Mn元素使得淬火冷却速率对合金性能的影响更为显著。在水冷淬火条件下，0.3% Mn合金屈服强度较0 Mn合金强度提高约17%，而在风冷条件下反而比0 Mn合金低。结合淬火态试样的透射电镜显微组织揭示了其作用机理。本文的研究结果可为Al-Mg-Si挤压材的工业生产提供有益参考。

Abstract: Tensile test, optical metallography (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM) were conducted to study the effects of Mn addition on the microstructures and mechanical properties of Al-Mg-Si alloy with different quenching processes. It was found that the size of the matrix grain and the secondary particles were refined attributed to a trace of Mn addition, thus, the elongation of the alloys was increased. However, the Mn addition sig-nificantly increased the effect of quenching cooling rate on the alloys’ strength. On the water quenching condition, the yield strength of 0.3% Mn alloy was increased by approximately 17%, when compared with the 0 Mn alloy. But on the air quenching condition, its yield strength was lower than the 0 Mn alloy. The mechanisms of these phenomena were revealed by TEM observations on the samples in quenching temper. The results of this paper may provide favorable guidance for in-dustrial production of Al-Mg-Si extrusions.