In Situ Study on the Compression Deformation Behavior of MoNbTaVW High-Entropy Alloy

The excellent mechanical properties of high-entropy alloys make them advanced materials in science and technology. However, the underlying mechanism of plastic deformation is not well understood. In situ experiments are urgently required to provide a fundamental understanding of the plastic deformation under high pressure. We performed in situ synchrotron x-ray diffraction experiments to study compression deformation behavior of MoNbTaVW in a radial diamond anvil cell. Our results show that the strength and ratio of the stress-to-shear modulus values are ~1.5 and 3 times of that of pure tungsten, respectively. MoNbTaVW yields at around 5 GPa and then developed a much stronger texture as compared with pure W. This work provides clear evidence that active dislocation behavior is mainly responsible for the high strength in MoNbTaVW under compression. The unique technique also opens a new avenue to investigate the in situ mechanical properties and their mechanisms in other types of alloys.