Effects of Pre-ageing on Microstructure and Mechanical Properties of T9I6 Treated 2519A Aluminium Alloy
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The effects of pre-ageing on the microstructure and mechanical properties of T9I6 treated 2519A aluminium alloy were investigated by hardness testing, tensile testing, transmission electron microscope, high resolution transmission electron microscope and differential scanning calorimetry. With the increase of pre-ageing time from 40 min to 4 h, the strength tends to increase first and then decrease; the pre-ageing time of 80 min results in the highest 0.2% proof strength and ultimate tensile strength of 491.9 and 513.8 MPa, respectively, and a high elongation of 14.6%. Pre-ageing is favorable for the formation of a number of primary GP zones, which can greatly improve the distribution of dislocations introduced by subsequent pre-deformation and secondary GP zones introduced by subsequent interrupted ageing. As a result, the number of precursors for θ′ hardening precipitates is maximized and the mechanical properties is improved after final re-ageing.
Keywords2519A aluminium alloy Pre-ageing Mechanical properties Microstructure
This study is supported by the National Key Research and Development Program of China (No. 2016YFB0300901), the Shenghua Yuying Project of Central South University (20130603) and China Scholarship Council Program (201706375013).
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