Fatigue crack growth and fracture behavior of bismuth-doped copper bicrystals

Journal Article · Sat Jul 01 04:00:00 EDT 1989 · Metallurgical Transactions, (Section) A: Physical Metallurgy and Materials Science; (USA)

DOI:https://doi.org/10.1007/BF02647404· OSTI ID:5266896

Chikwembani, S ^[1]; Weertman, J ^[2]

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1. Chancellor College, Box 280, Zomba, Malawi (IR)
2. Northwestern Univ., Evanston, IL (USA). Dept. of Geological Sciences

The authors discuss rate measurements in Cu-Bi bicrystals which have shown that for a given cyclic stress intensity factor {Delta}{Kappa}, the crack growth rate da/dN increases with increasing Bi concentration. The increase in da/dN is due to the surface energy reduction that occurs because of the presence of bismuth in the copper. For a given by crystal orientation, the Paris exponent m was found to increase with increasing bismuth content. The m value was found to be between about 0.5 and 3. This finding points to the need for fatigue crack growth theories that incorporate a variation in m in their crack growth laws. The grain boundary fracture surfaces of weak bicrystals showed steps whose formation is thought to arise from the need for bismuth to segregate to low energy surfaces. The results also indicate that the fracture surface energy of weak bicrystals can be lower than that of pure bismuth.

• OSTI ID: 5266896
• Journal Information: Metallurgical Transactions, (Section) A: Physical Metallurgy and Materials Science; (USA), Journal Name: Metallurgical Transactions, (Section) A: Physical Metallurgy and Materials Science; (USA) Vol. 20A:7; ISSN MTTAB; ISSN 0360-2133
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102 -- Metals & Alloys-- Structure & Phase Studies
360103* -- Metals & Alloys-- Mechanical Properties
ALLOYS
BISMUTH ADDITIONS
BISMUTH ALLOYS
COPPER ALLOYS
CRACK PROPAGATION
CRYSTAL DOPING
CRYSTAL STRUCTURE
FATIGUE
FRACTURE PROPERTIES
GRAIN BOUNDARIES
GRAIN ORIENTATION
LAYERS
MECHANICAL PROPERTIES
MICROSTRUCTURE
ORIENTATION
STRESSES
VARIATIONS