TiNi shape memory alloy (SMA) specimens have been subjected to tension carried out at various strain rates. The goal was to investigate a nucleation and development of the stress-induced martensitic transformation by infrared (IR) and acoustic emission (AE) techniques. Therefore, both the infrared radiation and acoustic emission data were recorded using a fast infrared camera and acoustic emission setup , respectively. It has been shown that the initial, macroscopically homogeneous transformation initiates in the elastic stage of the deformation even before the stress-strain curve knee and formation of the localized transformation bands. It has also been found that the homogeneous transformation occurs at similar stress level for all strain rates applied, while the localized martensitic transformation depends on the strain rate. Nucleation and development of the localized transformation bands, detected by the infrared camera, were confirmed by acoustic emission technique. The differences between the IR and AE activities were recorded during the TiNi SMA loading and unloading process, manifesting different dynamics of the stress-induced martensitic forward and reverse transformation.

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The object of the work was to find the temperature fields and their evolution during tensile test and simple shear test of metal in order to use them in the examination of material's behaviour. In initial stage of metal's elongation, the temperature distribution allows to determine the beginning of plastic deformation. In the homogeneous state of stress temperature measurements enable to investigate a process of energy storage during the plastic deformation. Heterogeneous temperature distribution observed in the subsequent, advanced state of deformation are related to evolution of the localized plastic deformation, leading to necking and damage. Furthermore, examination of the temperature distribution obtained during static simple shear test enables us to confirm the occurrence of macroscopic shear bands, calculated in theoretical approach.