Monotonic mechanical properties of titanium grade 5 (6Al-4V) welds made by microplasma

Abstract

The research concerned the possibility of using the microplasma welding technique for joining thin titanium alloy Grade 5 (6Al-4V) sheets. For this purpose, titanium reference samples without welds (Type 1) and two types of welded joints (butt joint - Type 2 and Type 3 overlap joint) were made with selected microplasma welding parameters for which strength parameters were determined and compared with the strength of the native material. The assessment of the connection quality was made on the basis of a monotonic tensile test. A metallographic analysis of the welded joints was made and the breakthroughs sample obtained during the tests was also carried out. In addition, strain distributions were determined in loaded sample types, which allowed investigating the impact of the heat affected zone size on the strength of welded joints subjected to monotonic tensile tests and Vickers hardness tests. Microplasma welded joints displayed relatively high brittleness. The failure locations are still influenced by heat affected zone despite the highly concentrated plasma beam of the microplasma arc welding.