2001 Volume 42 Issue 10 Pages 2112-2116
The stress relaxation experiment has been performed at temperatures ranging from room temperature to 1073 K to study changes in motion and structure of the dislocations induced into the Co–Ni-based alloy. The resultant zero rate of stress relaxation at room temperature can be assumed to be due to the immobilization of the induced dislocations originating from an elastic interaction between dislocation cores and solute atoms. At elevated temperatures where the dynamic strain aging (DSA) occurs, the zero rate of the stress relaxation at an initial stage can be attributed to the dislocation locking effect caused by the Suzuki segregation. The stress relaxation at the DSA temperature range occurs by the sole movement of leading partial dislocations, resulting in wide dislocation dissociations. At exceeding the DSA temperature range, the dislocation locking effect caused by the Suzuki segregation fades away and the two partial dislocations simultaneously glide by viscous motion, resulting in the lack of the observed wide dislocation dissociation. The phase diagram calculation and microstructure observations reveal that the present alloy SPRON 510 is a supersaturated solid solution and that the occurrence of the Suzuki segregation is strongly associated with the degree of the supersaturation of the solid solution.