Al-Mn中间合金对Mg-Al-Mn系合金组织及高温力学性能影响的研究

发布时间：2018-06-22 19:11

  本文选题：Al-Mn中间合金 + AM合金　； 参考：《武汉科技大学》2016年硕士论文

【摘要】：镁合金具有质量轻、比强度高、减振性能好以及可回收利用等方面的优势,使其在汽车工业中的应用正快速增长。AM60镁合金由于制造成本低、工艺性能好,是应用较广泛的一类铸造镁合金,但该合金的高温性能差,阻碍了其应用范围,因此提高合金的高温性能成为广大镁合金工作者感兴趣的研究课题。本研究首先制备了两种成分的Al-Mn中间合金,然后在镁液中添加中间合金制备AM60A和AM61A镁合金。采用光学金相分析,SEM及能谱分析研究了镁合金的显微组织及相成分,对镁合金进行室温和高温拉伸试验,研究了Al-Mn中间合金对AM合金力学性能的影响,结合固溶及时效组织分析了Al-Mn中间合金提高AM合金高温性能的原因。研究结果表明:添加Al-Mn中间合金能够有效改善AM合金组织中β-Mg17Al12形态和分布,减少了粗大共晶β-Mg17Al12相数量和尺寸,增加了颗粒状的β-Mg17Al12相,镁合金的室温力学性能明显提高;同时,加快冷却速度可以细化镁合金的晶粒尺寸;Al-Mn相是一种热稳定的高温相,450℃,45小时保温也不能使其溶解,因此添加Al-Mn中间合金能够明显提高AM合金的高温强度;AM合金在250℃时效处理时还可以形成许多细小颗粒状耐高温相,有利于AM合金高温性能的提高,AM61A合金由于含有更多的Al-Mn组织,因而高温强度最高。
[Abstract]:Magnesium alloy has the advantages of light weight, high specific strength, good vibration absorption performance and recyclable utilization. The application of AM60 magnesium alloy in automobile industry is increasing rapidly because of its low manufacturing cost and good process performance. It is a kind of casting magnesium alloy which is widely used, but the high temperature property of the alloy is poor, which hinders its application scope. Therefore, improving the high temperature property of the alloy has become an interesting research topic for many magnesium alloy workers. In this study, two kinds of Al-Mn master alloys were prepared firstly, and then AM60A and AM61A magnesium alloys were prepared by adding master alloys to magnesium solution. The microstructure and phase composition of magnesium alloy were studied by optical metallographic analysis (SEM) and energy dispersive spectrum (EDS). The tensile tests at room and high temperature were carried out on the magnesium alloy. The effect of Al-Mn master alloy on the mechanical properties of AM alloy was studied. The reason of improving the high temperature properties of AM alloy by Al-Mn master alloy was analyzed in combination with solution and aging microstructure. The results show that the addition of Al-Mn master alloy can effectively improve the morphology and distribution of 尾 -Mg17Al12 in AM alloy, decrease the number and size of coarse eutectic 尾 -Mg17Al12 phase, increase the granular 尾 -Mg17Al12 phase, and improve the mechanical properties of magnesium alloy at room temperature. The grain size of magnesium alloy can be refined by increasing the cooling rate. The Al-Mn phase is a kind of thermostable high-temperature phase, which can not be dissolved by 45 hours of heat preservation at 450 鈩，

本文编号：2053927