Influence of Post-Weld Processing Techniques on Laser Beam-Welded Al–3Mg–0.25Sc Alloy Sheets

Barat, K and Panbarasu, K and Bathe, R and Venkateswarlu, K (2020) Influence of Post-Weld Processing Techniques on Laser Beam-Welded Al–3Mg–0.25Sc Alloy Sheets. Transactions of the Indian Institute of Metals, 73 (6). pp. 1461-1468. ISSN 09722815

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Abstract

Fusion welding in aluminium alloys had always remained an issue for aero- and auto industries. An Al– 3Mg–0.25Sc alloy is classified as weldable aluminium alloys. In this study, two welding techniques, keyhole and conduction welding, have been used for joining Al–3Mg– 0.25Sc sheets of thickness 1.6 mm. Experiments were carried out using different beam diameter (0.16– 2 mm dia), beam power (2–4.5 kW) and laser head speed (ranging from 0.5 to 6 m/min). The results for all autogenous key- hole welding clearly demonstrated a drop in ductility (\ 0.8%) compare d to base metal for all beam power and welding speed combinations although the yield strength was reas onably good (175–180 MPa, i.e. [ 50% of base metal). Residual stress-induced distortions affected the final shape of the product, and for that, a suitable stress relief annealing was also required. Hereby, we chose two heat treatment schedules: (1) solution treatment and annealing and (2) retrogression and re-ageing. Retrogres- sion and re-ageing is a precipitation-controlled phe- nomenon and comprises of an intermediate annealing step between tempering and solutionizing temperature to dis- solve the nano-clusters present in the matrix (retrogression) and re-precipitating and growing them by ageing (re-age- ing). These two steps were repeated cyclically, and as a result, the strength (190 MPa) and ductility (* 9%) of the material were improved substantially. The improvement of ductility and strength was explained in detail in the light of microstructural studies.

Item Type: Article
Uncontrolled Keywords: Al-3Mg-0.25Sc alloy Post weld treatment Strength Ductility Weldment Laser welding
Subjects: CHEMISTRY AND MATERIALS > Chemistry and Materials (General)
Depositing User: Smt Bhagya Rekha KA
Date Deposited: 18 Aug 2021 11:48
Last Modified: 18 Aug 2021 11:48
URI: http://nal-ir.nal.res.in/id/eprint/13450

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