Effect of hot compression on the microstructure evolution of aluminium bronze alloy

Abstract

This work aims to study the flow behaviour, phase transformation, and microstructure evolution of aluminium bronze (Cu–9Al–4Fe) alloy. The hot compression behaviour of aluminium bronze were studied using simulator isothermal hot compression tests investigated at strain rates of 0.01–10 s−1 and temperature of 500–800 °C. According to the construction of constitutive equation and three-dimensional hot processing maps, the activation energy was 275.64 kJ/mol. The precipitated fine κⅣ particles during hot compression inhibit grain growth; the coarse κⅡ particles promote dynamic recrystallization through the mechanism of particle-stimulated nucleation (PSN). The formation of deformation twins under the influence of the fine κⅣ particles and high-density annealing twins are formed by stacking fault energy (SFE). Phase transformation by hot compression of the material at 500–800 °C, where the structure consists of the α phase and (α + γ2) eutectoid structure to α + β phase, is important for the increase in the power dissipation factor. Adiabatic shear leads to wedge-shaped cracks at 500 °C and 600 °C, 10 s−1, which pass through the (α + γ2) eutectoid structure and α phase interface with coarse-phase particles. The discontinuous dynamic recrystallization (DDRX) mechanism is the dominant DRX mechanism for aluminium bronze, in which DDRX, characterized by grain boundary bulging, was activated. The strengthening mechanism of aluminium bronze includes dispersion strengthening, twin strengthening, and grain refining strengthening during hot deformation, which leads to the increased activation energy of aluminium bronze alloy.

Keywords

• Aluminium bronze alloy
• Flow behaviour
• Dynamic recrystallization
• Phase transformation
• Strengthening mechanism