(1. 南昌大学材料科学与工程学院,南昌 330031;
2. 南昌大学江西高性能精确成形重点实验室,南昌 330031)
摘 要: 提出流变成形的两个本质问题,即卷入性缺陷和晶间偏析,两者是流变成形材料的力学性能一致性差、综合力学性能没有竞争力或不明确的本质因素,是阻碍设计和优化流变成形专用合金的重要因素。开发无卷入性缺陷半固态浆料的制备方法和工艺是研究和发展流变成形首要解决的关键问题,对此提出获得优质半固态浆料的三项原则。同时,总结晶间偏析的4种表现形式,提出将“晶间偏析”作为流变成形专用合金的设计准则之一。
关键字: 流变成形;半固态浆料;卷入性缺陷;晶间偏析;合金设计
(1. School of Materials Science and Engineering, Nanchang University, Nanchang 330031, China;
2. Key Laboratory of Net Forming in Jiangxi Province, Nanchang University, Nanchang 330031, China)
Abstract:Two unique issues in rheoforming were introduced, which are the entrainment defects formed during the semi-solid slurry preparation, and the intercrystalline segregation formed during the further solidification of semi-solid slurry. These two unique issues are significantly important factors that lead to the worse consistency of mechanical properties, which make the rheoforming components more weakly competitive and restrict the developing of design and optimization of alloys specially used for rheoforming. It is crucial for rheoforming to create preparation methods that can produce semi-solid slurry without entrainment defects. For this, three rules have been present. The intercrystalline segregation is derived from the special microstructure and composition of residual liquid in semi-solid slurry. It displays itself in four forms, and should be used as one of criteria for the composition design of alloys specially used for rheoforming.
Key words: rheoforming; semi-solid slurry; entrainment defects; intercrystalline segregation; alloy design