LF6铝合金超塑性研究

本文对硬状态LF6铝合金板材的超塑性进行了研究。发现这种状态的合金,不需专门的预处理,就可呈现出很显著的超塑效应,其延伸率可达463％。力学特性和金相研究结果表明,LF6铝合金由于第二相粒子的作用,可以获得细小、稳定的晶粒,因而其超塑效应十分显著。此合金超塑变形的主要机制是晶界滑移,起调节作用的机制主要是品内滑移。本文的研究工作可使某些合金超塑成形的预处理工作结合在原材料生产过程中进行,从而可以简化超塑成形的工艺过程,扩大这种新工艺的应用范围。

A STUDY OF THE SUPERPLASTICITY OF LF6 ALUMINIUM ALLOY

Tn this paper the superplasticity of cold-rolled sheet metal of LF6 aluminium alloy was studied. An extremely significant superplastic effect can be attained in cold-rolled condition without any special pre-treatment. Total elongation as high as 463%. can be achieved under the following conditions:490℃ and 3.33 ×10-4s-4.The corresponding strain rate sensitivity index m = 0.68 and flow stress o=2.8 MPa. As compared with the da- ta available in the literature, the above results are in the lead at home and abroad. The results of mechanical tests and metallographic examinations indicated that the presence of the particles of second phases such as B（Mg2Al3）, MnAl6. and TiAl3 leads to the formation of fine and stable grains necessary for achieving superplasticity. The most probable deformation mechanisms for superplastic flow of LF6 aluminium alloy are grain boundary sliding accommodated by the sliding within grains. The results presented in this paper may pave the way for incorporating the pre-tre-amment necessary for superplastic forming of certain alloys in the processing of sheet products. As a result, the superplastic forming processes can be simplified and the application of the new technology to industry can be expanded. The achievements of this study have been put into practice and the results were excellent. The authors have made some suggestions to the metallorgical department in order to popularize the achievements as early as possible.