氧化铝夹杂破碎与弥散行为的试验研究

金属零件基体中的非金属夹杂物不可避免且对基体力学性能影响严重，而锻造变形是使非金属夹杂物在金属基体中破碎和弥散的主要途径。以钢中常见的Al₂O₃硬性夹杂为研究对象，采用粉末冶金技术与3D打印熔覆成形技术相结合的方法制备了内含不同气孔率Al₂O₃夹杂的金属试样。进行含Al₂O₃夹杂金属试样在系列变形条件下的锻造试验，通过变形后Al₂O₃夹杂的形貌观察，研究分析了夹杂气孔率和锻造工艺参数（变形温度、变形速度、变形路径）对Al₂O₃夹杂破碎及弥散行为的影响。结果表明，夹杂气孔率越高，越易发生破碎行为。降低变形温度或提高变形速度可促进较高气孔率Al₂O₃夹杂的破碎及弥散；对于具有较低气孔率的Al₂O₃夹杂，提高变形温度是加剧其破碎程度的主要方式。同时变形路径的复杂化可显著提高Al₂O₃夹杂的破碎程度，促进其在金属基体中进一步的弥散。

Experimental Study on Crushing and Dispersion Behavior of Alumina Inclusions

Functional Graded Material (FGM) is a new type of composite material composed by two or more materials with continuous gradient changes. Nowadays, it has received extensive attention in engineering field. However,traditional FGM preparation techniques cannot meet the requirement from the industry area such as aviation, medical, military etc. As a newborn technology, additive manufacturing (AM) provides a totally different FGM preparation principle. Introduction of available FGM preparing technology based on AM is focused, and the research status and important application of titanium-based, iron-based and metal-ceramic based FGM prepared by laser cladding and selective laser melting is further discussed. Moreover, the principle and research progress of continuous FGM prepared by selective laser melting is presented with the undergoing work from our research group. Finally, the challenges and opportunities of using additive manufacturing to prepare FGM are listed, and the future development direction of this field are prospected.