Uncovering the superior high-temperature structural stability of molybdenum single crystal via added Re element

The Mo-14Re alloy is considered to be the best reactor structural material for fast space nuclear reactors. In this work, the structure stability of the < 111 > -oriented Mo-14Re single crystal at high temperature was investigated by comparing the microstructure evolution of the < 111 > -oriented pure Mo single crystal under different strains. Thermal simulation tests show that the critical dynamic recrystallization deformation of the < 111 > -oriented pure Mo single crystal at 1400℃ is between 15 % and 20 %, and the < 133 > orientation has the advantage of preferential nucleation. Furthermore, the < 001 > //CD fiber texture is generated in the < 111 > -oriented pure Mo single crystal subjected to 50 % hot deformation. The Re element is conducive to inhibiting the dynamic recrystallization of the < 111 > -oriented Mo single crystals, which is because the addition of Re makes the sub-grain difficult to form the size difference between the adjacent sub-grain. These uniform sub-grains results in an insufficient misorientation gradient to form an effective recrystallization nucleus, leading to the monocrystalline structure of the < 111 > -oriented Mo-14Re single crystals.