Characterization of hot deformation behavior of brasses using processing maps: Part I. α Brass

The constitutive flow behavior of α brass in the temperature range of 500°C to 850°C and strain rate range of 0.001 to 100 s−1 has been characterized with the help of a power dissipation map generated on the basis of the principles of the Dynamic Materials Model. The map revealed a domain of dynamic recrystallization in the temperature range of 750°C to 850°C and in the strain rate range of 0.001 to 1 s−1, with a maximum efficiency of power dissipation of about 54 pct. The optimum hot working conditions are 850°C and 0.001 s−1, and these match with those generally employed in industrial practice. In the temperature range of 550°C to 750°C and strain rates lower than 0.01 s−1, the efficiency of power dissipation decreases with decreasing strain rate, with its minimum at 650°C. In this regime, solute drag effects similar to dynamic strain aging occur to impair the hot workability. The material undergoes microstructural instabilities at temperatures of 500°C to 650°C and at strain rates of 10 to 100 s−1, as predicted by the continuum instability criterion. The manifestations of the instabilities have been observed to be adiabatic shear bands