Real-time observations of transformations in steels

Real-time observations can help determine problems that are otherwise difficult to prove. For example, the hgh-resolution determination of the growth rate of plates of bainite that are too fine to resolve using hot-stage optical or laser-confocal microscopy; the development of surface relief as a sample of austenite transforms by a displacive mechanism. Proof that austenite does not undergo a separation into carbon-rich and carbon-poor domains prior to phase transformation. Acoustic emissions that place a lower limit to the rate of transformation. The simultaneous real-time monitoring of the development of stress, dimensional change and phase change to design novel welding alloys that leave little in the way of residual stress on reaching ambient temperature.

A lecture given by Harry Bhadeshia, for the Mettle'22 series organised by the National Institute of Technology, Tiruchirappalli, India.

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