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在AM60B镁合金熔炼过程中加入混合稀土Y,Gd并辅以超声熔体处理工艺制备合金,利用光学显微镜(OM)、透射电镜(TEM)和万能试验机,研究了添加复合稀土和超声处理对镁合金微观组织和力学性能的影响,分析了其作用机制。结果表明,添加混合稀土Y,Gd后,未经超声处理的试样,稀土化合物存在于合金组织中,阻碍了位错和晶界滑移,α-Mg基体晶粒明显细化,β相减少,合金抗拉强度σ_b和延伸率δ分别达到257 MPa和9%,强度提高约20%。施加超声处理能进一步细化合金组织,使得α-Mg基体晶粒更加等轴细小,抑制β相在晶界处的连续网状分布。稀土相趋于弥散均匀分布,促进了稀土元素的细晶强化作用,使合金抗拉强度提高到269 MPa,延伸率达到11%。当稀土添加量超过一定范围后,稀土相开始粗化并割裂基体,这时超声处理对合金组织的改善作用有限,合金力学性能呈现下降的趋势。
In the process of smelting AM60B magnesium alloy, mixed rare earth Y and Gd were added and the alloy was prepared by ultrasonic melt treatment. The effects of adding rare earth composite and ultrasonic treatment on the mechanical properties of the alloy were studied by optical microscope (OM), transmission electron microscope (TEM) and universal testing machine Magnesium alloy microstructure and mechanical properties of the impact of its mechanism of action. The results show that the samples without rare earth elements and rare earth compounds exist in the alloy microstructure after adding mixed rare earths Y and Gd, which hinders the dislocation and grain boundary sliding. The α-Mg matrix grains are obviously refined and the β phase is reduced , Alloy tensile strength σ_b and elongation δ reached 257 MPa and 9% respectively, and the strength increased by about 20%. Ultrasonic treatment can further refine the alloy structure, making the α-Mg matrix grains more equiaxed and smaller, inhibit the β network in the grain boundary continuous mesh distribution. Rare earth facies tended to disperse uniformly and promoted the fine grain strengthening effect of rare earth elements. The tensile strength of the alloy was increased to 269 MPa and the elongation reached 11%. When the amount of rare earth exceeds a certain range, the rare earth phase began to roughen and split the matrix, then the role of ultrasonic treatment on the improvement of the alloy is limited, the mechanical properties of the alloy showed a downward trend.