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The influence of boron-doping on the effectiveness of grain boundary hardening in Ni{sub 3}Al

Journal Article · · Acta Materialia
;  [1];  [1];  [2];  [3]
  1. City Univ. of Hong Kong, Kowloon (Hong Kong). Dept. of Physics and Materials Science
  2. Univ. of Birmingham (United Kingdom). School of Metallurgy and Materials
  3. Central Iron and Steel Research Inst., Beijing (China)
The influence of boron-doping on the effectiveness of grain boundary hardening in Ni{sub 3}Al has been investigated by measuring microhardness profiles across grain boundaries of binary and boron-doped Ni{sub 3}Al bicrystals. It was found that although boron gives rise to significant solution strengthening in Ni{sub 3}Al, the effectiveness of grain boundary hardening in Ni{sub 3}Al is lessened by the addition of boron. Furthermore, the contribution of grain boundary hardening to the overall strength decreases as the segregation extent of boron at the grain boundary increases. A theoretical model of grain boundary hardening considering the various effects of boron-doping has been developed. Application of the model can deconvolute the individual effects of boron-doping on solution hardening, distribution of microcavities along grain boundaries and the interaction of dislocations on different slip systems. Analyzing the experimental results with the model suggests that boron-doping can (1) improve the transfer efficiency of shear stress across a grain boundary by reducing the amount of microcavities along the grain boundary; (2) suppress the hardening effect from the interaction of dislocations moving on different slip systems; and (3) cause a significant solution hardening effect.
OSTI ID:
353473
Journal Information:
Acta Materialia, Journal Name: Acta Materialia Journal Issue: 6 Vol. 47; ISSN 1359-6454; ISSN ACMAFD
Country of Publication:
United States
Language:
English