Processing map and hot deformation mechanism of novel nickel-free white copper alloy
(1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education,
Central South University, Changsha 410083, China;
3. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China)
2. Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education,
Central South University, Changsha 410083, China;
3. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China)
Abstract: Hot compression test of a novel nickel-free white alloy Cu-12Mn-15Zn-1.5Al-0.3Ti-0.14B-0.1Ce (mass fraction, %) was conducted on a Gleeble-1500 machine in the temperature range of 600-800 °C and the strain rate range of 0.01-10 s-1. The constitutive equation and hot processing map of the alloy were built up according to its hot deformation behavior and hot working characteristics. The deformation activation energy of the alloy is 203.005 kJ/mol. An instability region appears in the hot deformation temperature of 600-700 °C and the strain rate range of 0.32-10 s-1 when the true strain of the alloy is up to 0.7. Under the optimal hot deformation condition of 800 °C and 10 s-1 the prepared specimen has good surface quality and interior structure. The designed nickel-free alloy has very similar white chromaticity with the traditional white copper alloy (Cu-15Ni-24Zn-1.5Pb), and the color difference between them is less than 1.5, which can hardly be distinguished by human eyes.
Key words: Ni-free white copper alloy; hot compression deformation; constitutive equation; processing map