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采用镧铈型混合稀土对过共晶Al-28%Si活塞合金进行了变质处理,对其显微组织和力学性能进行了研究。结果表明:与单一稀土铈变质相比较,镧铈型混合稀土对该合金具有较好的变质效果,初晶硅的尺寸基本保持在20μm左右,且尖角大多钝化呈团球化状,共晶硅呈短杆状均匀分布;合金经过混合稀土变质后,晶界处产生复杂化合物组织起到了弥散强化作用,使其综合力学性能明显提高,尤其是高温强度的显著提高,已完全满足活塞合金在使用性能上对高温强度的要求。
The microstructure and mechanical properties of the hypereutectic Al-28% Si piston alloy were modified by lanthanum-cerium mixed rare earths. The results show that lanthanum-cerium-type mischmetal has a better metamorphism than that of single rare earth cerium. The size of the primary silicon remains at about 20μm, and most of the sharp corners are passivated into clusters. Silicon alloy is short rod-like uniform distribution; alloy after mixed rare earth metamorphism, the grain boundary complex compounds have played a role in the organization of dispersion strengthening, significantly improved its mechanical properties, especially at high temperature strength has been significantly improved, has fully met the piston alloy In the use of performance requirements of high temperature strength.