Bismuth-induced embrittlement of copper grain boundaries.
Catastrophic brittle fracture of crystalline materials is one of the best documented but most poorly understood fundamental phenomena in materials science. Embrittlement of copper by bismuth is a classic example of this phenomenon. Because brittle fracture in any structural material can involve human tragedy, a better understanding of the mechanisms behind it is of the highest interest. In this study, we use a combination of two state-of-the-art atomic characterization techniques and ab initio theoretical materials simulations to investigate the geometric and electronic structure of a copper grain boundary with and without bismuth. Only with this unique combination of methods are we able to observe the actual distribution of bismuth in the boundary and detect changes in the electronic structure caused by the bismuth impurity. We find that the copper atoms that surround the segregated bismuth in the grain boundary become embrittled by taking on a more zinc-like electronic structure.
Oak Ridge National Laboratory, Condensed Matter Sciences Division, Oak Ridge, Tennessee 37831-6030, USA.
Gerd
G
Duscher
Matthew F
MF
Chisholm
Uwe
U
Alber
Manfred
M
Rühle
D001729:Bismuth / Q000737:chemistry*; D003198:Computer Simulation; D003300:Copper / Q000737:chemistry*; D003460:Crystallization / Q000379:methods*; D004548:Elasticity; D006244:Hardness; D008422:Materials Testing / Q000379:methods*; D008669:Metallurgy / Q000379:methods*; D008956:Models, Chemical; D008958:Models, Molecular; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D013499:Surface Properties
D003300:Copper; D001729:Bismuth