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研究不同压力凝固条件下Mg82.13Zn13.85Y4.02(质量分数,%)合金微观组织和力学性能,发现合金的凝固组织是由a-Mg基体,W-Mg3Y2Zn3和I-Mg3YZn6相组成.其中,常压下凝固组织中的a-Mg枝晶间分布着由共晶组织形态和杆状第二相组成的网状结构.随着凝固压力的增大,共晶网逐渐断开,其数量逐渐减少,a-Mg基体中Zn的溶解度逐渐增大.常压凝固合金的室温压缩强度为344 MPa,屈服强度为331 MPa,相对压缩率为16%.6 GPa,1250℃凝固合金的室温压缩强度可达455 MPa,屈服强度426 MPa,相对压缩率为25%.常压凝固合金的压缩断裂模式为典型的解理断裂,且解理面大而光滑平整,高压凝固合金的压缩断口解理面较小,并出现撕裂岭和类似“撕裂韧窝”的形貌特征,解理断裂的程度有所降低.
The microstructure and mechanical properties of Mg82.13Zn13.85Y4.02 (mass fraction,%) alloy under different pressure and solidification conditions were investigated. The results show that the solidified microstructure of the alloy consists of a-Mg matrix, W-Mg3Y2Zn3 and I-Mg3YZn6 phases, At atmospheric pressure, the a-Mg dendrites in the solidified structure are distributed in a network structure composed of eutectic microstructure and rod-like second phase. With the increase of solidification pressure, the eutectic network gradually breaks down and the number gradually increases The solubility of Zn in a-Mg matrix increases gradually.The room-temperature compressive strength of atmospheric solidified alloy is 344 MPa, the yield strength is 331 MPa, the relative compressibility is 16% .Compressive strength at room temperature of 6 GPa and 1250 ℃ solidified alloy Up to 455 MPa, yield strength of 426 MPa and relative compressibility of 25% .The compression fracture mode of normal pressure solidified alloy is a typical cleavage fracture, and the cleavage plane is large and smooth. The cleavage cleavage plane of the high pressure solidified alloy Smaller, and tearing ridge and similar “torn dimple ” topography, the degree of cleavage fracture decreased.