摘要
采用光学显微镜(OM)、透射电镜(TEM)、X射线衍射(XRD)和拉伸试验机等研究了Zr含量对2524铝合金显微组织及力学性能的影响。结果表明:添加Zr元素能够明显细化铸态2524铝合金的晶粒。铸态合金存在明显的枝晶偏析,经过均匀化退火处理后,非平衡低熔点相基本溶入基体,晶间组织分布趋于均匀。大应变轧制变形后,2524铝合金中均得到了典型的纤维状组织,合金中的第二相主要为S(Al_2CuMg)相,θ(Al_2Cu)相、T(Al_(20)Cu_2Mn_3)相和Al_3Zr相,并沿晶界呈连续分布。经时效处理后,形成大量弥散的Al_3Zr粒子,对位错和亚晶界具有强烈的钉扎作用,能明显提高合金的抗再结晶能力和室温力学性能。随着Zr含量的增加合金力学性能呈现递增趋势,当Zr含量为0.5 mass%时,2524铝合金的抗拉强度、屈服强度和伸长率分别为645 MPa、548 MPa和11%。
Effect of Zr content on microstructure and mechanical properties of 2524 aluminum alloys was investigated by means of optical microscope(OM), transmission electron microscopy(TEM), X-ray diffraction(XRD) and tensile tester. The results show that the grain size of the as-cast 2524 aluminum alloys can be refined significantly by adding Zr element. There is obvious dendritic segregation in the as-cast alloy, and after homogenization annealing treatment, the non-equilibrium low-melting phases are basically dissolved into the matrix, and the distribution of intergranular microstructure is more uniform. After the large-strain rolling deformation, typical fibrous microstructure is obtained in the 2524 aluminum alloys, and the second phase in the alloy are mainly S(Al_2CuMg), θ(Al_2Cu), T(Al_(20)Cu_2Mn_3) and Al_3Zr phases, which are distributed continuously along the grain boundaries. After aging treatment, a large number of dispersed Al_3Zr particles are formed in the alloys, have a strong pinning effect on dislocation and sub-grain boundaries, and can significantly improve the anti-recrystallization ability and room temperature mechanical properties of the alloy. With the increase of Zr content, the mechanical properties of the alloys are improved. When the content of Zr is 0.5 mass%, the tensile strength, yield strength and elongation of the 2524 aluminum alloy are 645 MPa, 548 MPa and 11%, respectively.
引文
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