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研究了Ca元素对450℃热轧350℃退火1 h的Mg-2Al-x Ca(x=0,0.2,0.5,1.0,2.0;mass%)显微组织、力学性能、腐蚀性能的影响。用光学显微镜、扫描电镜、能谱仪和极化曲线等综合分析了钙元素的微观作用机制。结果表明,少量钙元素主要以固溶形式存在,随着钙元素增多,形成了Mg17(Al,Ca)_(12)、Al_2Ca等含钙相粒子,使得晶粒不断细化、强度不断增加、耐蚀性能不断下降。其中,Mg-2Al-0.5Ca合金的综合性能最优,抗拉强度为232 MPa,伸长率为20%,极化曲线自腐蚀电位-1.49 V,自腐蚀电流密度208.92μA·cm~(-2)。
The effects of Ca on the microstructure, mechanical properties and corrosion resistance of Mg-2Al-x Ca (x = 0,0.2,0.5,1.0,2.0; mass%) annealed at 450 ℃ for 1 h at 350 ℃ were investigated. The microscopic mechanism of calcium element was comprehensively analyzed by optical microscope, scanning electron microscope, energy dispersive spectrometer and polarization curve. The results show that a small amount of calcium exists mainly in the form of solid solution. With the increase of calcium, calcium-containing phase particles such as Mg17 (Al, Ca) _12 and Al_2Ca are formed and the grains are continuously refined and their strength increases. Corrosion resistance continues to decline. Among them, Mg-2Al-0.5Ca alloy has the best comprehensive properties, the tensile strength is 232 MPa, the elongation is 20%, the self-corrosion potential of polarization curve is -1.49 V, the self-corrosion current density is 208.92μA · cm ~ 2).