Composition redistribution‐induced dynamic failure of dual‐phase 90W‐Ni–Fe alloy during adiabatic shear localization process
Lei Zhang, Jia‐Tao Zhou, Biao Chen, Yao Wang, Yuxuan Ma, Juan Wang, Yufeng Huang, C.H. Liang, Wensheng Liu
Abstract
Abstract With the upgrade of armor protection materials, higher requirements are put forward for the penetration performance of tungsten alloy kinetic energy armor‐piercing projectiles, and the penetration performance is closely related to the adiabatic shear band under extreme stress conditions. Here, the detailed analysis of the adiabatic shear band microstructure evolution of a dual‐phase 90W‐Ni–Fe alloy under a high strain rate was conducted by combining advanced electron microscopic characterization, while discussing shear fracture from a mechanical perspective under thermoplastic instability. The high temperature and high stress environment inside the adiabatic shear band led to the refinement of the W phase and γ‐(Ni, Fe) phase grains to the submicron level, and induced the elements redistribution of W, Ni, and Fe to precipitate W nanocrystalline with hardness as high as 11.7 GPa along the recrystallization grain boundaries of the γ‐(Ni, Fe) phase. Mechanical incompatibility caused by the hardness difference between W nanocrystalline and γ‐(Ni, Fe) phases led to a strain gradient at the interface. The microvoids preferentially nucleated at the W nanocrystalline/γ‐(Ni, Fe) phase interface, then merged to form microcracks and grew further, leading to shear failure.