Effect of variation of strain rate on thermal and acoustic emission during tensile deformation of nuclear grade AISI type 316 stainless steel

Abstract

A systematic study has been undertaken to correlate the changes in thermal and acoustic emissions during tensile deformation of AISI type 316 nuclear grade stainless steel (SS) due to variations in the strain rate. Strain rates were varied in the range 3.3 x 10^-4s^-1 to 1.7 x 10^-2s^-1. Thermal emissions were monitored using a focal plane array based thermal imaging system. For a given strain rate, the rate of increase in temperature was observed to be gradual and uniform in the work hardening zone, and to increases drastically during necking. With increasing strain rate, the temperature also increased. Based on the experimental results a constitutive equation can be modelled relating the rise in temperature to strain rate. In the case of acoustic emission (AE), the root mean square (RMS) voltage of the AE signal and cumulative counts increase with strain rate due to the increase in source activation. The peak amplitude distribution of AE hits has shown that hits with similar peak amplitude are generated for all strain rates.