Transactions of Materials and Heat Treatment

Title：Effect of pre-deformation on high temperature uniform deformation for AA6011 aluminum alloy thin-walled tubes

Authors： Yang Song1 Zheng Kailun2 Yuan Shijian1

Unit： 1. School of Materials Science and Engineering Harbin Institute of Technology 2. School of Mechanical Engineering Dalian University of Technology

KeyWords： pre-deformation aluminum alloy thin-walled tubes hot gas bulging uniform deformation initial pre-deformation amount

ClassificationCode：TG316.8

year,vol(issue):pagenumber：2023,48(5):7-15

Abstract：

The uniform deformation capacity at high temperature of high strength aluminum alloy tubes with different initial pre-deformation amounts was investigated to simulate the influence of pre-bending and pre-forming processes on the subsequent gas bulging process in the hot gas bulging forming of actual complex special shape tubes. The digital image correlation (DIC) testing method was used to conduct high temperature tensile tests on aluminum alloy specimens with different initial pre-deformation amounts under typical hot gas bulging process parameter conditions of the temperatures of 400 and 450 ℃ and the strain rates of 0.01 and 0.1 s-1. The obtained true stress-true strain curves show that the introduction of initial pre-deformation amount leads to a significant softening of materials during the high temperature deformation process and the decreasing trend of flow stress increases significantly with the increasing of initial pre-deformation amount. The strain field of the specimen obtained by DIC was processed using the Spatio-temporal method to obtain uniform strain values under different conditions, the uniform strain value decreased from 0.28 without initial pre-deformation amount to 0.15 with the initial pre-deformation amount of 15%. Compared to the traditional Nakajima method, this method is able to obtain accurate strain values at the moment of sudden change for thickness, and the uniform strain level at the moment before fracture is slightly lower, the obtained results are more conservative. This study can provide initial pre-deformation amount design boundaries for the preforming of practical multi-step hot gas bulging to meet the uniform deformation requirements of final formed parts by hot gas bulging.

Funds：

国家自然科学基金资助项目（5200052525）

作者简介：杨松（1984-），男，博士，高级工程师，E-mail：20B909114@stu.hit.edu.cn

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