钙元素含量对Mg-2Al-xCa-0.2Gd镁合金织构演变和性能的影响

The Influence of Calcium (Ca) Content on the Texture Evolution and Mechanical Properties of Mg-2Al-xCa-0.2Gd Magnesium Alloys

摘要:

在镁合金中加入适量钙元素，具有细化晶粒、提高强度和耐热性能等优点。本文通过OM、SEM、EBSD、XRD等分析手段，研究了不同钙含量对Mg-2Al-xCa-0.2Gd (x=0.2, 0.5, 1.0, 2.0; mass%)合金晶粒尺寸、织构和力学性能的影响。研究结果表明：随着钙含量的不断增多，合金晶粒尺寸不断减小，强度不断增加。但织构具有不同的演化规律，{0001}<11 0>基面织构组分不断降低，而包含<11 3>方向的锥面织构组分呈现出先增加后减小的趋势，导致合金的延伸率和杯突值先增加后减小。当钙含量为0.5%时，合金表现出最强的横向分裂织构特征，综合力学性能最优，最大强度为238MPa、最大延伸率为22%、杯突值为4.31mm。

Abstract:

The addition of proper amount of calcium to magnesium alloys can refine grain size, enhance strength and heat-resistant. The influence of different contents of calcium (Ca) on the grain size, texture and mechanical properties of Mg-2Al-xCa-0.2Gd (x=0.2, 0.5, 1.0, 2.0; mass%) were investigated in this paper through the OM, SEM，EBSD and XRD techniques. The results showed that with the increase of the Ca content the grain size gradually decreased which leads to the improvement of strength. However, the texture evolution had different characterization such as the decrease of {0001}<11 0> texture, the firstly increase and then decrease of the pyramidal texture components containing the <11 3> direction, which resulted in the corresponding change of elongation and Erichsen value. The magnesium alloy with 0.5% calcium content exhibited bimodal texture characterization and showed the best mechanical properties with the maximal tensile strength of 238MPa, the total elongation of 22% and the Erichsen value of 4.31mm.