Improvements in Welding Properties of Titanium Through the Use of Interlayers

This article presents some recent results from fusion welding of titanium alloys with interlayers. Without an interlayer, the CP Ti weld typically results in comparable hardness across the weld and base material (BM). However, for α alloys, near-α alloys and α + β alloys, the fusion zone (FZ) and heat-affected zone (HAZ) show high hardness compared with the BM. Inversely, β alloys have FZ and HAZ with lower hardness compared with BM. Under loading, the presence of areas with high or lower hardness could affect the load distribution across the weldments. Post-welding heat treatment (PWHT) is sometimes employed to minimise or avoid this situation. However, for large-size components, PWHT is not practical. In this investigation, we show that by selecting a proper interlayer the above issues can be minimised; hence, PWHT may not be necessary, leading to cost reduction and process efficiency.