Hot compression behavior, microstructure and texture competitive evolution of α/β phases in Cu-40Zn-1.6Pb duplex brass

Most previous studies concerning hot deformation of dual-phase leaded brass separately investigate microstructural evolution of individual phases, while the fundamental mechanisms underlying microstructural regulation induced by coordinated deformation between αCu and β-CuZn phases remain ambiguous. In this work, hot compression tests are systematically performed to explore the flow behavior, microstructure and texture evolution of Cu-40Zn-1.6Pb alloy at temperatures of 550-750℃ and strain rates ranging from 0.01 to 10s-1. On the basis of Murty’s instability criterion, three-dimensional power dissipation maps and hot processing maps are established under different strain levels. The optimal stable processing window is determined as 600-700℃, 0.1-1s-1. Within this regime, DRX can be simultaneously triggered in both phases, and the power dissipation efficiency continuously rises with increasing strain. Regions under high strain rates are susceptible to flow instability. The unstable domain expands as strain accumulates, accompanied by localized deformation. EBSD quantitative characterization reveals distinct grain boundary characteristics, GOS distributions and grain size evolution for the two phases, demonstrating disparate hot deformation responses. The microstructural evolution of the α-Cu phase is controlled by deformation twinning, TDRX and grain growth, resulting in a pronounced <001>∥AD​ texture. By contrast, plastic softening of the β-CuZn phase is dominated by CDRX, and its texture components exhibit remarkable temperature dependence. A critical finding is that mechanical coupling and deformation incompatibility between the two phases hinder the simultaneous achievement of sufficient dynamic recrystallization and grain refinement in both α-Cu and β-CuZn phases. This work establishes an intrinsic correlation between macroscopic hot processing windows and microscopic structural evolution of the dual-phase alloy. The competitive and synergistic deformation mechanism of Cu-40Zn-1.6Pb alloy during hot deformation is clarified, offering theoretical guidance for the targeted optimization of hot forming procedures for leaded brass.