Progress in the development and application of low phase transformation temperature materials in metal manufacturing

This paper reviews the recent advancements in the development and application of low transformation temperature (LTT) materials in metal manufacturing, with a focus on welding and additive manufacturing (AM) processes. LTT materials mitigate tensile residual stresses and distortions by inducing volume expansion during phase transformation, counteracting thermal contraction effects. The design principles of LTT alloys, including the influence of alloying elements on transformation temperatures, are discussed. Applications in single-pass and multi-pass welding demonstrate significant improvements in fatigue life, cracking resistance, and corrosion performance. However, challenges remain in multi-pass welding, where factors such as interpass temperature, dilution, and layering strategies affect residual stress distribution. In AM, LTT materials show promise in controlling residual stresses, particularly in laser- and arc-based processes, but further research is needed to optimize their use with different energy sources. Despite their potential, issues such as high costs, alloy design complexity, and performance optimization need to be addressed. Overall, LTT materials offer a promising approach to enhancing the performance of metal-manufactured components, though further advancements are required for widespread industrial adoption.