Diagram of grain growth modes

Despite grain growth process has been known for about a century, still there are unresolved problems. The main one is the following: what are microstructure characteristics necessary for changing the mode of grain growth from normal to abnormal. By numerical simulations we derived diagram displaying areas of different growth modes in coordinates grain size – pinning force. Normal grain growth takes place at very low pinning forces. At small grain sizes, abnormal grain growth is predominant. At larger grain sizes, abnormal growth develops in much more restricted range of pinning forces; above this range, grain growth is suppressed. These results allow formulating some general rules for controlling the grain structure. Diagram of grain growth modes [Display omitted] •Grain growth at different initial grain sizes and drag forces is numerically modelled.•Magnitudes of pinning force at the start and suppression of abnormal growth are found.•Diagram of grain growth modes basing on these data is constructed.•It shows areas of normal and abnormal growth in coordinates grain size – pinning force.•Abnormal growth is shown to be the predominant growth mode at small grain sizes.