摘要
利用X射线衍射分析方法分析了高压下凝固的Al-Ni-Y合金的相组成;利用光学显微镜对在不同条件下制备的高压凝固合金的显微组织形貌和共晶组织形貌进行研究;通过显微硬度测试方法,确定出冷却速度与显微硬度之间的关系。实验结果表明,高压条件下凝固的合金共晶点发生偏移,使得常压共晶成分的合金在高压下变成亚共晶成分合金。在5 GPa超高压力、不同冷速(50、100、200 K/min)条件下凝固的合金的显微组织形貌发生了很大的改变,但是合金的相组成没有发生变化。随着冷却速率的不断提高,合金组织逐渐细化,二次枝晶间距也随之减小,共晶团尺寸也更加细小,显微硬度提高,Al3Y相的各向异性逐渐减弱。
The phase constitution of Al-Ni-Y alloy solidified at high pressure was characterized by X-ray diffraction （XRD）. The microstructures of the samples were observed by optical microscope. The relationships between cooling rate and micro-hardness were determinate by micro-hardness testing. The results show that the microstructure of the alloy contains a lot of primary -Al, which suggests that the eutectic point of Al-Ni-Y alloy at high pressure shifts towards the Ni and Y directions in the phase diagram compared with that at ambient pressure. There is no new phase in the alloy solidified at high pressure under different cooling rates. With the cooling rate increasing, the growth morphology of eutectic structure changes significantly and the eutectic structure refines. In addition, with the cooling rate increasing, the secondary dendrite arm spacing decreases, the corresponding micro-grain size decreases, the micro-hardness increases, and the anisotropy declines, whose structures are transformed from characters-like to block-like to lamellar-like.
出处
《铸造技术》
CAS
北大核心
2015年第3期712-715,共4页
Foundry Technology
关键词
高压凝固
冷却速率
二次枝晶间距
各向异性
high pressure solidified
cooling rate
secondary dendrite arm spacing
anisotropy
作者简介
付莉超，女，河北唐山人，硕士，研究方向：金属材料力学行为与试验．电话：18633961303，E-mail：zhaoxin3151707@163．com
