The Microstructure Quantitative Anslysis Of Welded Joints On Aerospace High Strength Aluminum Alloy

Weld joints are the weakest parts in the manufacture of welded structure on high-strength aerospace aluminum alloy. Under heat welding, weld metallurgical defects, uneven joint organizations have become an important factor for joint comprehensive performance of solid solution hardening type aluminum. The past analysis and evaluation of the joint performance was limited mostly to the qualitative understanding of the impact of certain factors in the welding process, lack of a more comprehensive method of quantitative analysis and assessment to explain the relationship. Between welded joint organization performance and heat input as well as thermal cycling.Research and development of the subject work is as follows:(1) Analyze and evaluate the welded joints organization quantitatively by using optical image quantitative analysis system. Study the relevance of heat thermal cycling on welded joints organization and the characterization microstructure of optimization, in order to gain the quantitative understanding of the relationship between welding processes and some factors, such as welding heat input, thermal cycling characteristics, weld joints defects generated and the organization state;(2) Observe and evaluate the porosity, scale and distribution of pores on weld cross-section and weld fracture, in order to obtain the regular understanding of pore location and status. Propose more than 2% of porosity as a quantitative basis of joint performance prediction and failure analysis.(3) Make a quantitative expression of the degree of the grain boundary precipitation and aggregation, also strengthening phase desolventizing after solution heat cycle welding on 2219 aluminum alloy by observing the grain boundary width.This article proposes a quantitative analysis method to strengthen the mechanism of welding process optimization on solution high-strength aluminum alloy welding, a necessary complement to X-ray inspection and assessment of aluminum alloy welded joints methods, which has an important engineering significance to improve and enhance the performance of weld joints for 2219 and similar high-strength aluminum alloy.