2024 年 88 巻 11 号 p. 288-296
The complex microstructure coexisting dislocation, Co precipitation and Co2P precipitation is formed during the thermal process after cold deformation of Cu-Co-P alloy which is one of the practical precipitation-hardening copper alloys. The understanding of linkage of this complex microstructure and property (S-P Linkage) is an important issue to express the superior balance of strength, ductility and electric conductivity.
In this study, the microstructure information simulated based on N model coupled with dislocation recovery model and property information measured through experiments are analyzed using Principal Component Analysis (PCA) to clarify S-P Linkage. Furthermore, the new approach that combines linear additivity rule in the theory of alloy strengthening mechanism and PCA is proposed.
As a result, the following mechanisms were proposed: the immobilization of dislocations due to Co2P precipitation on dislocations and the remobilization due to coarsening of precipitation on dislocations rate-limit the dislocation recovery and affect balance between strength and ductility which have an antinomic relationship. Especially, the superior balance of strength and ductility is due to strengthening by immobilization of dislocations and sequential triggering of following phenomenon in the plastic region, (1) the high-speed motion of mobilized dislocation in bulk matrix phase, (2) the deposition of mobilized dislocations on grain boundaries and (3) the parabolic strain hardening.
