Loss in coherency and coarsening behavior of Cr precipitates in Cu-Ag-Cr alloy
(1.School of Materials Science and Engineering, Xi’an University of Technology, Xi’an 710048, China2.School of Materials Science and Engineering, Henan University of Science and Technology, Luoyang 471003, China)
Abstract: The coarsening behavior of Cr precipitates in Cu-0.1Ag-0.5Cr alloy was investigated, and the effects of aging processes on the microstructure and properties were discussed. The results show that the radius for coherent/semi-coherent transition of the Cr precipitates is determined from TEM micrographs as 1545nm. The calculated value of critical radius for a particle begining to lose coherency is about 12.5nm. The coherent (r<15nm) precipitates are found to coarsen and become semi-coherent during the passage of low-angle boundaries during recovery. The passage of high-angle boundaries through semi-coherent precipitates during recrystallization occurs by migration of the particle, resulting in the precipitates maintaining semi-coherent with the new grain.
Key words: Cu-Ag-Cr alloy； coherency； semi-coherency； aging