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采用宏观硬度、力学拉伸试验,研究了Si含量对汽缸Al-Sr铝合金组织及力学行为的影响。结果表明:随着Si含量增加到18%,Si共晶相为珊瑚状,α(Al)共晶相变成枝晶,Si初晶相消失。晶粒的平均粒径随Si含量上升而不断下降。随着Si含量的增加,Al-Si-Sr铝合金硬度出现了缓慢的上升趋势,该合金的拉伸强度与屈服强度逐渐上升,伸长率的变化规律出现不稳定状态。综合考虑Al-Si-Sr铝合金的力学性能,Si含量取18%是相对比较好的。添加Si后合金断口形貌呈大量细小密集的韧窝,是典型的韧性断裂。
The influence of Si content on the microstructure and mechanical behavior of Al-Sr aluminum alloy cylinder was studied by macro-hardness test and mechanical tensile test. The results show that as the Si content increases to 18%, the Si eutectic phase is coral-like, and the α (Al) eutectic phase changes to dendrite, and the Si primary phase disappears. The average grain size decreases with increasing Si content. With the increase of Si content, the hardness of Al-Si-Sr aluminum alloy shows a slow upward trend. The tensile strength and yield strength of Al-Si-Sr alloy gradually increase, and the variation of elongation shows an unstable state. Considering the mechanical properties of Al-Si-Sr aluminum alloy, Si content of 18% is relatively good. Adding Si alloy fracture morphology was a large number of small dense dimples, is a typical ductile fracture.