Transactions of Nonferrous Metals Society of China The Chinese Journal of Nonferrous Metals

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中国有色金属学报

ZHONGGUO YOUSEJINSHU XUEBAO

第9卷    第4期    总第33期    1999年12月

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文章编号:1004-0609(1999)04-0694-06
CP276铝锂合金的应变时效工艺
蒋  呐1   向曙光1   郑子樵2

(1. 西南铝加工厂技术中心, 重庆401326; 2. 中南工业大学材料科学与工程系,长沙410083)

摘 要: 研究了预拉伸量和时效温度对CP276铝锂合金组织与性能的影响。结果表明,时效前的预拉伸可促进 T1相异质形核,显著提高合金的沉淀强化效果,但同时指出,过大的预拉伸量(>6%)导致位错胞状缠结, 降低 T1 相分布的均匀性,对合金性能不利。时效温度则对晶界PFZ影响显著,高温时效的合金PFZ较宽,强度与塑性很差。该合金的最佳应变时效制度为:3%~6%预拉伸+160℃时效16~20h,该制度下合金具有较好的综合力学性能(σb=563MPa, σ0.2=521MPa, δ=6.6%)。

 

关键字: 铝锂合金;时效;组织;性能

Strain-ageing process for Al-Li alloy CP276
Jiang Na1 , Xiang Shuguang1 , Zheng Ziqiao2

1. Technology Center, Southwestern Aluminium Fabrication Plant, Chongqing 401326, P.R.China
2. Department of Materials Science and Engineering,
    Central South University of Technology, Changsha 410083, P.R.China

Abstract:Effects of the pre-ageing stretch and ageing temperatures on the microstructure and mechanical properties for Al-Li alloy CP276 were investigated. The results show that stretch before ageing promotes the heterogeneous nucleation of T1 precipitates throughout the matrix and hence increases the ageing strengthening effect of this alloy significantly. However, over-stretching (>6% ) results in cellular tangles of dislocations, which decreases the uniform distribution of T1 precipitates inside the grains, and therefore, deteriorates the strength and ductility of the alloy to some extent. The results also show that, ageing temperatures affect morphologies of precipitation free zones along grain boundaries remarkably. Alloy aged at high temperature exhibits wider PFZ , corresponding to the poor combination of strength and ductility. As a result, the favorable strain-ageing process for this alloy is that pre-ageing stretching 3%~6%+ageing at 160 ℃ for 16~20 h, upon which the alloy achieves desirable strength-ductility balance, i.e., σb is 563 MPa, σ0.2 is 521 MPa, δ is 6.6%, respectively.

 

Key words: Al-Li alloys; ageing strengthening; structure; property

ISSN 1004-0609
CN 43-1238/TG
CODEN: ZYJXFK

ISSN 1003-6326
CN 43-1239/TG
CODEN: TNMCEW

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