Effect of heat treatment on microstructure and mechanical properties of the Pt–10Ir alloy wires

This study investigates the influence of heat treatment on the microstructure and mechanical properties of Pt–10Ir alloy wires to achieve materials with stable quality. The wires (ϕ1.2 mm) were fabricated via a forging-rolling-multi-pass cold drawing process, with intermediate annealing applied during drawing. The microstructural evolution, including grain size, texture, and recrystallization behavior, was characterized using optical microscopy and electron backscatter diffraction (EBSD). The relationship between heat treatment parameters, microstructure, and properties was established, leading to the development of an optimized two-stage heat treatment process. The results indicate that the heat treatment of Pt–10Ir wire involves dislocation recombination (recovery), recrystallization nucleation and growth, and texture-selective strengthening, governed by the interplay between solute drag effects and recrystallization kinetics. The optimum two-stage heat treatment process (850°C-60 min +950°C-40 min) significantly enhances ductility, achieving an elongation of approximately 30 %, which is a sixfold increase compared to the as-drawn state, while maintaining adequate strength.