摘要
在真空感应炉中氩气保护下制备材料 ,采用OM ,SEM ,EDAX和XRD及拉伸试验 ,研究分析了硅对原位反应自生Mg2 Si/ZM5复合材料铸态显微组织和性能的影响规律。结果表明 ,反应添加物Si在ZM5合金中形成了高熔点、高硬度的Mg2 Si强化相 ,明显地提高了材料的室温与高温强度 ,如Si的质量分数为 1.5 %时 ,室温抗拉强度与屈服强度提高幅度分别可达 2 0 .1%和 61.5 % ,Si的质量分数为 1.0 %时 ,高温抗拉强度与屈服强度提高幅度分别可达 14 .9%和 2 5 .7% ;Mg2 Si相的形貌随着硅含量的不同而变化 ,如Si的质量分数为 0 .5 %时 ,主要生成细小短棒状或片状共晶Mg2 Si相 ,Si的质量分数大于1%时 ,则出现了粗大块状或汉字状初生Mg2 Si相和片状或短棒状的共晶Mg2 Si相 ;由于所生成的Mg2 Si相本身是一种脆性相 ,使得该材料呈现出解理断裂 ,降低了材料的塑性。
Mg 2Si/ZM5 Mg composites were prepared by vacuum induction furnace under the protection of Ar gas atmosphere. The effects of Si on as cast microstructure and properties of in situ Mg 2Si/ZM5 composites were observed and analyzed by means of OM,SEM, EDAX and XRD as well as tensile testing. The results showed that Mg 2Si intermetallic compound with high melting point and high hardness formed by additive reactant Si reacting on ZM5 base alloy can greatly improve strength of the composites at both ambient and elevated temperatures. The tensile strength and yield strength at ambient temperature increased by 20.1% and 61.5% respectively with 1.5% Si addition, and at elevated temperature increased by 14.9% and 25.7% respectively with 0.5% Si addition. Morphology of Mg 2Si phase varied with Si content. It is fine short rod like or flake eutectic Mg 2Si with adding 0.5% Si, and become bulk or Chinese script primary Mg 2Si plus flake or short rod like eutectic Mg 2Si with increasing more than 1.0%Si addition. Owing to Mg 2Si brittle phase, the Mg 2Si/ZM5 matrix composite presented the cleavage fracture, resulting in decreasing its plasticity.
出处
《特种铸造及有色合金》
CAS
CSCD
北大核心
2003年第2期7-10,共4页
Special Casting & Nonferrous Alloys
基金
福州大学科技发展基金研究项目 [XKJ(YM) - 0 1 1 6]
