纳米钨在高压下的物理力学行为与尺寸效应研究OA北大核心CSTPCD

Exploring the influence of size effect on the physical properties of materials under high pressure is helpful for the development of new materials with novel or improved properties.The static compression behaviors of polycrystalline tungsten powder with average grain sizes of 30 and 65 nm under high pressure were studied by using diamond anvil cell(DAC)combined with synchrotron radiation X-ray diffraction respectively.By analyzing the peak position and the half-height width of the X-ray diffraction spectrum at each pressure,the unit cell volume,grain size,and microscopic strain of nano-tungsten metal under high pressure were obtained.By fitting the third Birch-Murnaghan equation,the bulk moduli of 30 and 65 nm tungsten are obtained to be 257(7)GPa and 343(8)GPa,respectively.Combined with the results of previous studies,it is found that when the gain size decreases from micron to 10 nm,the yield strength of tungsten at 10 nm increases by 3.5 times compared with that of microcrystal samples;the bulk modulus shows a tendency of increasing firstly and then decreasing,and the bulk elastic modulus of tungsten at 30 nm decreases by 25％compared with that of tungsten at 65 nm.