The brittle-ductile transition of tungsten single crystals at the micro-scale
作者： J. Ast , J.J. Schwiedrzik , J. Wehrs , D. Frey , M.N. Polyakov
DOI: 10.1016/J.MATDES.2018.04.009
关键词:
摘要: Abstract The loading rate effect on the brittle-ductile transition temperatures of tungsten single crystals at micro-scale was investigated by microcantilevers with a (100)[001] crack system. Specimens length to width height 15 μm/4 μm/6 μm were fabricated focused ion beam milling. At low (−90 −25 °C) samples failed brittle cleavage fracture, irrespective applied fracture toughness 3.2 MPa·m1/2. With increasing up 500 °C and depending rate, increased significant tip plasticity dislocation-controlled microcleavage observed means high resolution electron backscatter diffraction measurements performed after testing. respect macroscopic specimens, shift lower significantly activation energy 0.36 eV found. We explain this increase in flow stresses due sample size effects.
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