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为改善铸态AZ91镁合金组织不均匀性,提高其轧制成型能力,研究了均匀化退火处理对AZ91镁合金轧制变形前后微观组织及力学性能的影响。结果表明:均匀化退火处理可以有效改善合金组织中第二相分布;经400℃、多道次轧制后,沿晶界分布的细长条状Mg_(17)Al_(12)相数量显著减少,部分脆性Mg_(17)Al_(12)相发生断裂,以小颗粒状弥散分布于晶界附近和基体内部。均匀化后轧制合金比铸态轧制合金强度略有提高,而伸长率提高达50%。轧制后合金的拉伸断口形貌也显示合金塑性得到明显改善。
In order to improve the microstructure and mechanical properties of AZ91 magnesium alloy, the effects of homogenizing annealing on the microstructure and mechanical properties of AZ91 magnesium alloy before and after rolling deformation were studied. The results show that the homogenization annealing can effectively improve the distribution of the second phase in the alloy microstructure. The number of elongated Mg 17 Al 12 phases along the grain boundaries decreases significantly after multipass rolling at 400 ℃. , Part of the brittle Mg 17 Al 12 phase rupture, with small particles dispersed around the grain boundary and inside the matrix. After homogenization, the strength of the rolled alloy is slightly higher than that of the as-cast rolled alloy, while the elongation increases up to 50%. The tensile fracture morphology of the alloy after rolling also shows that the plasticity of the alloy is obviously improved.