Comparison of grain size and strain rate influences on higher temperature metal strength and fracturing properties

A review is given in honor of David Taplin's researches, with colleagues and students, on grain size aspects of the higher temperature plastic deformation and failure behaviors of metals and alloys. Comparison is made with lower temperature grain size strengthening measurements and their Hall-Petch (H-P) dislocation pile-up model description. One focus is on H-P prediction of the true fracture strain dependence on grain size or particle spacing. The second focus is on the relationship between the thermal activation based Zerilli-Armstrong (Z-A) relations for fcc or bcc metal strength levels and the historical Zener-Hollomon (Z-H) and Larson-Miller (L-M) parameters employed to describe the combination of higher temperature and lower strain rate, or creep type, results. Particular measurements are reviewed for copper, magnesium, copper-nickel Monel alloy, titanium, nickel, aluminum alloy and ferritic and austenitic steel materials.