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利用光学显微镜、X射线衍射仪、扫描电镜,研究了稀土Nd对AZ80镁合金组织和力学性能的影响。AZ80镁合金铸态组织由基体α-Mg和晶界处析出的粗大连续网状β-Mg_(17)Al_(12)相组成。添加Nd后,使原本粗大连续的β-Mg_(17)Al_(12)相转变为细小和断续分布,同时,合金中产生了形态分别呈杆状的Al_(11)Nd_3相和块状的Al2Nd稀土相。随着Nd元素添加量的增加,AZ80镁合金的铸态力学性能呈先提高后下降的趋势。当加入0.9%的Nd时,合金的铸态抗拉强度和屈服强度均达到最高,分别为205MPa和135MPa,伸长率达到7.5%。时效过程中稀土元素Nd抑制了片状β-Mg_(17)Al_(12)相的不连续析出,延迟合金达到峰时效的时间。T6处理后,AZ80-0.6Nd合金的抗拉强度和屈服强度最高,分别为221MPa和164MPa,伸长率为4.1%。
The effects of rare earth Nd on the microstructure and mechanical properties of AZ80 magnesium alloy were studied by optical microscope, X-ray diffraction and scanning electron microscopy. The as-cast microstructure of AZ80 magnesium alloy consists of α-Mg matrix and coarse continuous network β-Mg_ (17) Al_ (12) phase precipitated at the grain boundaries. After adding Nd, the coarse and continuous β-Mg_ (17) Al_ (12) phases were transformed into small and discontinuous distributions. At the same time, Al_ (11) Nd_3 phases and lumps Al2Nd rare earth phase. With the increase of Nd addition, the as-cast mechanical properties of AZ80 magnesium alloy first increased and then decreased. When 0.9% Nd was added, the as-cast tensile strength and yield strength of the alloy reached the highest values of 205MPa and 135MPa respectively and the elongation reached 7.5%. During the aging process, the rare earth element Nd inhibits the discontinuous precipitation of the sheet-like β-Mg_ (17) Al_ (12) phase and delays the peak aging time of the alloy. T6 treatment, AZ80-0.6Nd alloy tensile strength and yield strength of the highest, respectively 221MPa and 164MPa, elongation of 4.1%.