稀土Y与喷射沉积技术对铝铁合金组织和性能的影响

Effect of rare earth yttrium and spray forming technology on microstructure and properties of Al-Fe alloy

普通凝固条件下得到的铸造Al-Fe合金中存在粗大的针状或片状初生富铁相,严重割裂基体,引起应力集中,恶化合金性能。利用稀土Y对Al-6Fe合金进行微合金化处理,结合快速凝固技术,并辅以热挤压技术,获得较常规凝固条件下更加细小均匀的显微组织,以解决铝铁合金中粗大的针片状富铁相割裂基体的问题。实验结果表明,稀土元素Y抑制了初生富铁相生长的趋势,将粗大针片状富铁相细化为菱形和短棒状,一定程度上减小了合金的第二相尺寸;稀土Y微合金化结合快速凝固技术,使得铝铁合金中形成了细小弥散的三元Al-Fe-Y金属间化合物,极大细化了第二相,在改善组织形貌的同时提升了合金的硬度和屈服强度。

There are coarse acicular or flake primary iron-rich phases in the cast Al-Fe alloy obtained under ordinary solidification conditions,which seriously split the matrix,cause stress concentration and deteriorate the alloy performance.In this paper,Al-6Fe alloy was microalloyed with rare earth Y,combined with rapid solidification technology and assisted by hot extrusion technology,to obtain a finer and more uniform microstructure than that under conventional solidification conditions,so as to solve the problem that the coarse needle-like iron-rich phase in Al-Fe alloy splits the matrix.The results show that the growth trend of primary iron-rich phase is inhibited by rare earth element Y,and the coarse acicular iron-rich phase is refined into diamond and short rod shape,which reduces the second phase size of the alloy to a certain extent.The combination of rare earth Y microalloying and rapid solidification technology enables the formation of fine and dispersed ternary Al-Fe-Y intermetallic compound in Al-Fe alloy,which greatly refines the second phase and impromtes the hardness and yield strength of the alloy while improving the microstructure.