Microstructure in hot cracking mechanism of welded aluminium alloys

Abstract

Microstructure in the hot cracking mechanism was investigated via the Spot-Varestraint test to assess the sensitivity of hot cracking for three aluminium alloys, i.e. A2024-T351, A2219-T87 and A7050-T6, after gas tungsten arc welding. A stereomicroscope, an optical microscope and a scanning electron microscope were adapted to observe the microstructure of hot cracking mechanisms in the weld metal fusion zone (WMFZ), the weld metal heat affected zone (WMHAZ) and the partially melted zone (PMZ). The results indicate that the hot cracking structures differ: solidification cracking in the WMFZ and liquefaction cracking in the WMHAZ. An energy dispersive spectrometer was used to analyse the PMZ of WMHAZ to confirm the segregation of elemental Cu in the liquefaction cracking mechanism at grain boundaries.

Mechanical Properties of the AlCu4Mg1 Alloy Joint Manufactured by Underwater Friction Stir Welding

“…To overcome these difficulties, nonconventional welding techniques have been explored. These alternative methods make it possible to create complex structures while reducing the tensile strength of the joint [4][5][6][7]. By implementing these innovative welding techniques, it becomes possible to achieve high-quality welds and preserve the integrity and strength of the alloy, thus enabling the fabrication of complex components for various applications in the aerospace and automotive industries.…”

Investigation of 7075 aluminum alloy TIG welding joint using 7075 aluminum alloy wire before and after heat treatment

“…It is widely used in aerospace, military and national defence, rail transportation, shipbuilding and other fields [1][2][3][4]. 7075 aluminum alloy is a precipitated hardening alloy, due to its poor weldability, easy hardening cracking and over-aging in the heat-affected zone, it is difficult to weld by traditional welding methods such as TIG and MIG, which has become a bottleneck problem restricting its welding application [5][6][7][8][9][10][11][12][13][14].…”