Influence of sulphur content on the hot deformation behaviour and constitutive description of Cu-DHP alloy

The effect of sulphur content on the hot working behaviour of Cu-DHP alloy was investigated by hot compression testing. It was revealed that sulphur increases the flow stress, as critically discussed based on the constitutive analysis, leading to reliable and meaningful constitutive equations. The stress multiplier (α) was determined as 0.03 MPa⁻¹; while the hyperbolic sine exponent (n) was determined as 4.95 and 6.86 for the low- and high-sulphur alloys, respectively. Moreover, the high sulphur content resulted in a significant increase in the deformation activation energy (Q) from 274.1 for the low-sulphur alloy to 396.6 kJ/mol for the high-sulphur alloy, and it also hindered dynamic recrystallization (DRX), limiting the processing window. However, it led to finer DRX grain sizes for the conditions that the complete DRX was achieved. The results of this work provide insights into the processability and flow stress behaviour for metal forming applications. These findings are based on the deformation conditions, represented by the Zener-Hollomon parameter, and the presence of sulphur as an impurity element.