Sony Punnose

TL;DR: In this paper, acoustic emission (AE) generated during tensile deformation of smooth and notched specimens of near Alpha titanium alloy have been studied and a few tests carried out with both types of specimens were also interrupted in order to correlate with the damage mechanism.

Abstract: Determination of strain for initiation of rapid crack growth is vital for designing coated components for aerospace applications. Knowledge of such strain is useful for prevention of catastrophic failure of coated components. In the present study this critical strain has been determined during tensile deformation of aluminide coated near-α titanium alloy using infrared thermography. A single step on-line method of determination of stored energy change as a function of true plastic strain, that incorporates conduction heat loss correction in a simple way, has been used to determine such strain level. It is shown that beyond a strain level the crack ensemble that form becomes unstable and further straining leads to rapid crack growth in the coating that penetrates into the substrate material. This manifests in an unprecedented trend in the stored energy change that has been identified with the strain for inception of rapid crack growth.

TL;DR: In this paper, the evolution of microstructural damage during tensile deformation of a near-α titanium alloy has been characterised using nonlinear ultrasonic (NLU) parameters.

TL;DR: The microstructural changes of the fully heat treated alloy exposed at 980 °C for different hours of thermal exposure have been characterized using ultrasonic methods to non‐destructively characterize such detrimental changes in the microstructure that controls the mechanical properties and limits the life of components.

TL;DR: In this paper, the scale of crystal orientation change is shown to have a strong correlation with the degree of scatter in nonlinear ultrasonic (NLU) measurements, which arises due to anisotropy in harmonics generation as a result of orientation change of slip systems in polycrystals with respect to the wave propagation direction.