Solution and ageing heat treatments of ZK60 magnesium alloys with rare earth additions produced by semi-solid casting

Materials Research

Erenilton Pereira Da Silva²  Larissa Fernandes Batista²  Bruna Callegari²  Ricardo Henrique Buzolin²  Fernando Warchomicka¹  Guillermo Carlos Requena¹  Pedro Paiva Brito¹  Haroldo Cavalcanti Pinto² 

[1] ,Universidade de São Paulo Escola de Engenharia de São Carlos São Carlos SP ,Brasil

关键词: ZK60;    rare earth;    age hardening;    heat treatment;    thixocasting;   

DOI  :  10.1590/1516-1439.266214

来源: SciELO

【 摘 要 】

Rare earth elements reportedly improve high temperature strength and creep resistance of Mg alloys. In the present work, ZK60 Mg alloys containing different amounts (0.5, 1.5 and 2.5 wt.%) of rare earth additions were prepared by thixocasting and submitted to solution and ageing heat treatments (T4, T5 and T6). The as-cast and heat treated microstructures were investigated by scanning electron microscopy and hardness was evaluated as a function of heat treatment parameters. In the as-cast state, the alloys are formed by globular α-Mg grains reinforced by a network of composite Mg-Zn-RE precipitates with either smooth or lamellar/acicular morphologies. Solution of the smooth precipitates took place in alloys containing 0.5 and 1.5wt.%RE for T4-500 ºC but no precipitates were dissolved with T4-380 ºC. The optimum temperature for T5 and T6 was identified as 175 ºC, while T6-500 ºC led to the highest hardness, followed by T5 and T6-380 ºC, respectively.

【 授权许可】

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