Influence of welding parameters on mechanical and corrosion properties of Ti6Al4V alloy

Abstract

Ti6Al4V is an alpha–beta grade 5 titanium alloy, which is the most commonly used of all the titanium alloys. Ti6Al4V alloy possesses a lot of desirable properties such as, weldability, heat treatability and resistivity against corrosion. Due to its outstanding strength-to-weight ratio and low modulus of elasticity it is widely used in jet engines, aircraft fuselage and defence armour. In this investigation, an effort has been made to determine the optimal welding parameters in welding of 3 mm thick Ti6Al4V alloy plate using Gas Tungsten Arc Welding – with filler (GTAWF), Gas Tungsten Arc Welding – Autogenous (GTAWA) and Laser Beam Welding – Autogenous (LBWA) techniques and weldability of Ti6Al4V alloy. The GTAWF, GTAWA and LBW techniques are fusion welding techniques having the welding input parameters as Voltage V (volts), Current I (ampere) and Feed F (mm/minute). The response from these welding processes are Tensile strength T (MPa), Joint efficiency η(joint)(percent), Impact strength I (Joules) and Corrosion rate CR (mils/yr). The optimal welding parameters were determined with condition that the welding parameters had high mechanical properties (tensile strength, joint efficiency, impact strength) and minimum corrosion rate. The optimal welding parameters yielded GTAWF weldments that exhibited relatively excellent mechanical properties and corrosion resistance compared to LBWA, whereas GTAWA weldments exhibited a mediocre performance.