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通过金相显微镜、扫描电镜和力学性能测试分析了浇注温度对挤压铸造Al-2.75Li-1.52Cu合金组织和力学性能的影响。结果表明:浇铸温度对合金的微观组织影响很大,730℃浇注时,合金中柱状晶组织十分发达;较低的浇注温度可抑制柱状晶的生长,有利于等轴晶的形成。合金铸态的组织主要由α(Al)基体和T2(Al6Cu Li3)相组成,随着浇注温度的降低,T2共晶相数量增多,抗拉强度和伸长率增大,而屈服强度略微下降。浇注温度降低到670℃时,可获得全部为等轴晶的组织。
The effects of pouring temperature on the microstructure and mechanical properties of Al-2.75Li-1.52Cu alloy by squeeze casting were analyzed by metallographic microscope, scanning electron microscopy and mechanical testing. The results show that the casting temperature has great influence on the microstructure of the alloy. When the temperature is 730 ℃, the columnar crystal structure is well developed. The lower pouring temperature can inhibit the growth of the columnar crystal and is conducive to the formation of equiaxed grains. The as-cast microstructure of the alloy is mainly composed of α (Al) matrix and T2 (Al6Cu Li3) phase. With the decrease of pouring temperature, the amount of T2 eutectic phase increases, tensile strength and elongation increase while the yield strength decreases slightly. When the pouring temperature is lowered to 670 ° C, all equiaxed grains are obtained.