Strength of individual special tilt and twist boundaries in molybdenum bicrystals
Bicrystals with definite crystallographic parameters are very convenient model material for investigation of the grain boundary strength of refractory metals. In general, this approach, after accumulation of the certain experimental information, should create the opportunity for the understanding of the brittle intergranular fracture of cast and recrystallized molybdenum and tungsten. Besides misorientation angles and boundary types (twist and tilt), the important factor influencing boundary strength is the boundary plane. No account was, however, taken earlier of the effect of the grain boundary plane in intergranular brittleness. The previous methods employed to grow bicrystals, restricted significantly the possibilities of precise obtaining of the tilt grain boundaries with needed misorientation angles and preset boundary planes because of the use of electron-beam or electric arc welding of two single crystals. In a recent work a new technique for bicrystals growth was reported. It is interesting that at the same time the analagous technique was reported by Glebovsky et.al. The main advantage of the technique is opportunity to grow the bicrystals with correct tilt and twist boundaries. This work deals with the investigation of the fracture strength of special high-angle tilt and twist boundaries as a function of boundary plane and misorientation angle of bicrystal grains. The fracture strength of molybdenum bicrystals with tilt and twist boundaries nonmonotonously depends on the misorientation angle between the grains in bicrystals. There is a minimum in strength as a function of angle for the special boundaries. The fracture strength of special tilt and twist boundaries also depends on the nature of the boundary planes. The fracture strength and the interstitial content on both tilt and twist boundaries are the same but the precipitates distribution is different.
- Research Organization:
- Institute of Solid State Physics, Academy of Sciences of the USSR, Chernogolovka
- OSTI ID:
- 6393102
- Journal Information:
- Scr. Metall.; (United States), Vol. 19:4
- Country of Publication:
- United States
- Language:
- English
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