Dynamic shear response and microstructural evolution of laser-cladding Inconel 625 alloy

It provides theoretical guidance for the optimization of mechanical properties to research the dynamic shear mechanical properties and microstructural evolution law of laser-cladding Inconel 625（IN625） alloy. A series of dynamic shear experiments are conducted using the split Hopkinson pressure bar（SHPB）at varying ambient temperatures（20，600，800 ℃ and 1000 ℃）and strain rates（40000，60000 s−1 and 80000 s−1）. These experiments aim to establish the dynamic shear stress-strain relationship. Pre- and post-loading morphologies and crystal structures of the alloy are characterized using scanning electron microscopy（SEM）and electron backscatter diffraction（EBSD）. The results show that both the strain rate strengthening effect and temperature softening effect are pronounced in laser-cladding IN625 alloy，with temperature softening effect predominantly influencing its mechanical behavior at elevated temperatures. Compared to the unloaded sample，the dynamic shear test at room temperature lead to the development of a prominent shear texture，with an increase in dislocation density and a decrease in average grain size. Specially，the proportion of small-angle grain boundaries increases from 29% to 85%. Conversely，high-temperature dynamic shear experiments，compared to room temperature loading，weaken the preferred orientation and reduce the dislocation density of the crystals. These high-temperature conditions further decrease the average grain size and lower the proportion of small-angle grain boundaries from 85% to 73.5%.