Quantitative investigation of internal friction components in NiTiCu shape memory alloy using dynamic mechanical analyser and iterative method

This study primarily investigates the internal friction (IF) behaviour of Ti 50 Ni 48 Cu 2 (TNC2) shape memory alloy (SMA) through temperature, frequency, isothermal, and strain sweep analysis using a Dynamic mechanical analyser (DMA). The total internal friction (IF Total ) value of TNC2 alloy is 0.0686 at 323.4 K. The frequency sweep analysis reveals that increasing the frequency reduces the IF Total by 15.97% due to restricted martensitic interface movement. Isothermal analysis shows a significant drop in IF Total during the B2-B19′ transformation peak, with reductions of 79.02%, stabilising as intrinsic damping dominates. Strain sweep tests demonstrate that higher strain at isothermal temperature (323.4K) increases inherent internal friction (IF PT + IF Int ) B2–B19′ , with a frequency-dependent trend. The secondary focus is decomposing the IF Total into its intrinsic (IF Int ) and inherent internal friction (IF PT + IF Int ) B2–B19′ , components using an iterative method. The iterative method effectively separates IF Total , allowing precise calculation of the transformed volume fraction n(T). After eight iterations, convergence is achieved with a minimal error rate. The predicted IF spectrum closely matches experimental data, highlighting the method’s reliability for decomposing IF Total into its contributions.