【摘要】 在AZ91D合金中加入不同比例的稀土元素Nd进行合金化,并直接用于压铸试验。从所得压铸件上截取试样进行微观组织和断口形貌分析,对截取试样的室温和高温性能进行了测试。结果表明,少量稀土元素Nd的加入,对提高AZ91D合金常温力学性能的作用较小,疏松、夹杂等组织缺陷成为影响合金力学性的重要因素;合金中加入少量的稀土元素Nd后所形成的Mg12Nd等高熔点化合物,即可对合金晶粒起到钉扎作用,从而抑制晶界之间的滑移,阻碍位错的开动,有效地提高了合金的高温力学性能;合金在室温时表现为以解理断裂为主的脆性断裂,150℃拉伸时,合金拉伸断口上的韧窝数量明显增多且韧窝较深,还有大量的撕裂棱存在,拉伸断口整体上表现为以韧性断裂为主的混合断裂。更多还原

【Abstract】 The compression casting experiments has been done with two different ingredients magnesium alloys in this paper. The metallurgical structure and tensile fracture pattern of the pressure castings were investigated; also the room temperature and elevated temperature mechanical properties of samples were tested. The results indicate that a little rare earth has small effect on the room temperature mechanical properties of the alloys which lied on the amount of shrinkage porosity and impurity in the matrix, but the rare earth obvious improved the elevated temperature properties of the alloys. The tensile fracture patterns of samples mainly were brittle fracture as cleavage fracture at room temperature. When 150℃, the quantity of dimple and tearing arris were visibly increased on the fractures, and the tensile fracture patterns exhibited hybrid fracture as ductile rupture.更多还原