Abstract
Zr-6Al-0.1B alloy rich in Zr3Al phase is prepared by hot-pressing sintering. The thermal deformation behavior of sintered Zr-6Al-0.1B is analyzed by isothermal compression tests at deformation temperatures of 950, 1050, and 1150 °C with strain rates of 0.01, 0.1, and 1 s−1. The results indicate that at the early stage of thermal deformation, the stress increases rapidly with the increase of strain and then reaches the peak value. Subsequently, the stress decreases with the increase of strain under the softening effect. On the whole, the true stress-strain curve shifts to the high stress area with the increase of strain rate or the decrease of deformation temperature, so the sintered Zr-6Al-0.1B alloy belongs to the temperature and strain rate sensitive material. For the microstructure evolution of sintered Zr-6Al-0.1B during the isothermal compression, the high strain rate can improve the grain refinement. However, because sintered Zr-6Al-0.1B is a low plastic material, too high strain rate will exceed the deformation capacity of the material, resulting in an increase in defects. The increase of deformation temperature also contributes to grain refinement, but when the temperature is too high, due to the decomposition of Zr3Al phase, the deformation coordination of the material decreases, leading to the increase of the probability of the occurrence of defects. This study verified the feasibility of hot-pressing sintering to prepare Zr-6Al-0.1B alloy rich in Zr3Al phase and laid the foundation of “hot-pressing sintering + canning hot-extrusion” process of Zr-6Al-0.1B alloy components.
Highlights
The importance of lightweight, long life, and high reliability to spacecraft components is self-evident
Materials used by spacecraft components are mostly stainless steel and titanium alloy
The results show that B element can significantly refine the grain size of Zr3Al-based alloy
Summary
The importance of lightweight, long life, and high reliability to spacecraft components is self-evident. Yuan et al [14] investigated elastic and thermodynamic properties of the L12 type structure Zr3Al intermetallic compound under high pressure and temperature using ab initio plane-wave pseudopotential density functional theory (DFT) within the generalized gradient approximation (GGA). They found the elastic modulus and compressional and shear wave velocities are increasing monotonically with increasing pressure. The hot-pressing sintering temperature should be ensured within the formation conditions of Zr3Al, at the same time, it should be conducive to powder diffusion. Stop pressurizing when the temperature drops to 500 ◦C, and the furnace body and the graphite die are cooled by the circulation water outside the furnace
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