Article ID Journal Published Year Pages File Type
10620919 Acta Materialia 2006 13 Pages PDF
Abstract
The effect of Mn additions on the structural stability of electrodeposited Ni is investigated by comparing the microstructure evolution of Ni and Ni-Mn specimens with similar crystallographic initial textures. As deposited, Ni-Mn electrodeposits have a smaller crystallite size and substantially higher yield strength than Ni deposits, in agreement with the Hall-Petch relationship. Moreover, dilute Ni-Mn electrodeposits exhibit a thermal stability that significantly exceeds that of pure Ni. Indeed, Ni-Mn retains its texture, fine-grain microstructure, and strength above 500 °C (for 1 h anneal), and does not recrystallize up to 800 °C. In contrast, pure Ni with larger average grain size and similar preferred orientation shows abnormal grain growth at 300 °C and recrystallization at 600 °C. This study suggests two distinct temperature regimes. Below 600 °C, grain boundary segregation appears as a plausible mechanism for the thermal stability of Ni-Mn electrodeposits, whereas grain boundary pinning by precipitation contributes to the improved microstructural stability of Ni-Mn above 600 °C.
Related Topics
Physical Sciences and Engineering Materials Science Ceramics and Composites
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