WELD MICROSTRUCTURE REFINEMENT IN A 1441 GRADE ALUMINIUM-LITHIUM ALLOY

摘要

Clad 2 mm thick sheets of Russian 1441 grade Al-Li alloys were welded using a gas tungsten are welding process (GTAW). Comparisons were made between the weld beads obtained under (i) continuous current (CC), (ii) pulsed current (PC), and (iii) are oscillation (AO) conditions for their macro- and microstructural details. In the case of CC GTAW, sound welds could be produced only under a narrow range of welding parameters. Centre line cracks, which occurred in CC GTAW welds under certain conditions, were halted by switching to PC or AO conditions while the welding was in progress. Microstructural refinement was significant in the case of PC and AO GTA welding. [References: 19]