Study of heat source evolution during elastic-plastic deformation of titanium alloy Ti-0.8 Al-0.8mn based on contact and non-contact measurements

This work is devoted to investigation of the heat source evolution during quasistatic tensile testing of titanium alloy specimens using a contact heat flux sensor and infrared thermography. The purpose of the study is to evaluate the possibility of using two different measurement (contact and non-contact) methods to monitor the state of material by changing the heat source value registered on the specimen surface during deformation. The obvious advantages of infrared thermography are non-contact temperature measurements of the material surface under various conditions and heat source field calculations. However this method has a number of limitations associated with the reflectivity of the tested material, noisy signal caused by external factors, heat transfer conditions between the specimen and environment, and accuracy of heat source calculations. These problems do not allow using infrared thermography under operating conditions in order to evaluate the energy state of materials and structures. The paper attempts to verify the heat source value arising during the elastic-plastic deformation of the material using infrared thermography data. For this purpose, a Seebeck effect heat flux sensor has been developed by the authors. Contact sensor and infrared thermography data give time dependence of the heat flux value. The satisfactory agreement of the results shows that contact and non-contact measurements can be used either in combination (to verify the heat source value, its distribution over the material surface and heat exchange conditions for specimen and environment) or separately (as an express method to evaluate material conditions at different stages of loading).