Microstructural characterisation of laser beam and gas tungsten arc welded zirconium-2.5Nb

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Authors

Pistorius, Pieter Georg Hendrik

Journal Title

Journal ISSN

Volume Title

Publisher

Southern African Institute of Mining and Metallurgy

Abstract

The current study is intended to characterise the complex microstructure that results from autogenous welding of Zr-2.5Nb and its influence on mechanical properties. Laser beam welding (LBW) and gas tungsten arc welding (GTAW) were performed on a 1.5 mm thick samples by applying different combinations of speed and power to vary the heat input. The effect of cooling rate on β-α phase transformation temperature and the resulting microstructure was investigated using a Bahr dilatometer. In addition, mechanical properties were determined by tensile and hardness testing. The base metal microstructure consisted of a fine structure of Zralpha with a small fraction of Nb-beta phase. Both LBW- and GTAWwelded joints displayed similar martensitic microstructures, with the main difference being the weld geometry and strength.

Description

This paper was first presented at the AMI Precious Metals 2017 Conference ‘The Precious Metals Development Network’ 17–20 October 2017, Protea Hotel Ranch Resort, Polokwane, South Africa.

Keywords

Zr-2.5Nb, Autogenous welding, Microstructure, Laser beam welding (LBW), Gas tungsten arc welding (GTAW), Mechanical properties, β-α phase transformation temperature, Cooling rate

Sustainable Development Goals

SDG-09: Industry, innovation and infrastructure
SDG-12: Responsible consumption and production
SDG-13: Climate action

Citation

Mahlalela. S.S. & Pistorius, P.G.H. 2017, 'Microstructural characterisation of laser beam and gas tungsten arc welded zirconium-2.5Nb', Journal of the Southern African Institute of Mining and Metallurgy, vol. 117, pp. 947-953.