Dislocation pile-ups: From {1 1 0} cracking in MgO to model strength evaluations

The researches of Professor J.C.M. Li and his colleagues and students have been involved with dislocation pile-up descriptions in a number of ways: beginning from the interpretation of microindentation experiments on MgO single crystals, then carrying over to tabulation of various pile-up characteristics including those for dislocation loops expanding against the grain boundary resistance, and, lastly, interpreting grain size dependent material strength properties. The pioneering work is related here to accumulated pile-up results and Hall–Petch type interpretations also extending downwards in scale to nanocrystalline grain size materials.