The study of microstructure and mechanical properties on the dissimilar welding and post-weld heat treatment with A7075 / A7050 high strength aluminum alloys

• Main Authors: Lin,I Shin, 林宜勳
• Other Authors: Chou, Chang Pin
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/31071700542655814554

碩士 === 國立交通大學 === 工學院精密與自動化工程學程 === 101 === The article was investigated on the A7050 and A7075 dissimilar welding and it’s mechanical properties for post-weld heat treatment process. In this experiment, tungsten inert gas (TIG) welding process was utilized to make weldments with filler metals of ER5183 and ER5356 and ER5556. The effect of heat treatment of natural aging (T1), solution treatment(T4), and solution treatment plus artificial aging(T6) on the weldment were investigated. The tensile test, microhardness test, and optical microscope were used to study the mechanical properties and microstructures the effect of different trace elements on the material mechanical properties and microstructure is also determined. After T4 or T6 heat treatment, multiple precipitates were found in heat affected zone(HAZ) grain and grain boundaries. The microhardness, ultimate tensile strength, and yield strength of the heat treated weldment were greatly enhanced by the heat treatment. The fractured surface of T1 treatment shows dimple appearance indicating some ductility. In T6 treatment, some region maintain dimple surface, some region tend to brittleness cracking.