In-Situ Observation of Grain Boundary Behavior in Ni3 Al Alloys During Tensile Deformation in Sem

ABSTRACTThe deformation behavior of Ni3Al alloys with various chemical compositions and subjected to different heat treatments were in-situ observed in SEN. Moreover, in-situ observations of slip trace are supplemented by the direct observation of dislocation arrangements by TEM. In boron-doped Ni3Al alloys it is shown that close to the grain boundary there exists a thin slip transition region, within which slip lines are reoriented or other slip systems are operated to produce a local strain accommodation and to relax the stress concentration at grain boundaries. However, boron-enhenced ductility is seriously affected by alloy stoichiometry, the addition of a tertiary alloy element and heat treatment, etc.