Pre-treatment to Improve the Bake Hardening Response in the Naturally Aged Al-Mg-Si Aluminum Alloy

J. Mater. Sci. Technol. ›› 2011, Vol. 27 ›› Issue (3): 205-212.

Pre-treatment to Improve the Bake Hardening Response in the Naturally Aged Al-Mg-Si Aluminum Alloy

沈晉輝

Army Academy

收稿日期:2010-06-01 修回日期:2010-08-14 出版日期:2011-03-28 发布日期:2011-03-21
通讯作者: 沈晉輝

Pre-treatment to Improve the Bake-hardening Response in the Naturally Aged Al-Mg-Si Alloy

Chin-Hui Shen

Department of Mechanical Engineering, Army Academy No.750, Longdong Rd., Zhongli City, Taoyuan County 320, Taiwan, China

Received:2010-06-01 Revised:2010-08-14 Online:2011-03-28 Published:2011-03-21
Contact: Chin-hui Shen

摘要/Abstract

摘要： This paper describes pre-treatment methods that can improve the bake hardening response of naturally aged AA6022 (Al-0.6Mg-1.0Si) for use in automotive body panel applications. These methods are applied to accelerate the artificial aging process, which precedes the 30-day period of natural aging. The precipitation behavior of sheets of this aluminum alloy was analyzed using differential scanning calorimetry (DSC) as well as by measuring the electrical conductivity and subsequently confirmed by microstructure observations using transmission electron microscopy (TEM). Tensile tests and microhardness measurements were performed to determine the mechanical properties of the samples. Under the simulated paint bake conditions (30 min at 170 °C), the microhardness and the yield strength (YS) of the pre-strained and pre-aged samples were found to be 113 Hv and 225 MPa, respectively. These values are considerably higher than those of pre-aged samples. Moreover, they did not show any significant decrease during the initial stage of artificial aging

Abstract: This paper describes pre-treatment methods to improve the bake-hardening response of naturally aged AA6022 (Al-0.6Mg-1.0Si), which is an alloy used in automotive body panels. These methods are used to accelerate the artificial aging process, which proceeds 30-day period of natural aging. The precipitation behavior of the sheets of this aluminum alloy was analyzed by differential scanning calorimetry (DSC) and electrical conductivity measurements, and subsequently confirmed by microstructure observations by transmission electron microscopy (TEM). Tensile tests and microhardness measurements were performed to determine the mechanical properties of the samples. Under simulated paint-baking conditions (30 min at 170°C), the microhardness and the yield strength (YS) of the pre-strained + pre-aged samples were found to be 113 HV and 225 MPa, respectively. These values are considerably higher than those of pre-aged samples, and they did not decrease significantly during the initial stage of artificial aging.

Key words: Pre-aging, Pre-straining, Natural aging and Bake hardening

沈晉輝. Pre-treatment to Improve the Bake Hardening Response in the Naturally Aged Al-Mg-Si Aluminum Alloy[J]. J. Mater. Sci. Technol., 2011, 27(3): 205-212.

Chin-Hui Shen. Pre-treatment to Improve the Bake-hardening Response in the Naturally Aged Al-Mg-Si Alloy[J]. J Mater Sci Technol, 2011, 27(3): 205-212.

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