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以难熔金属纯Mo粉末为原料,采用高压扭转工艺在350℃温度和1.5GPa压力下制成相对密度为96.45%的金属Mo坯,利用多种检测手段分析了高压扭转过程中Mo粉颗粒孔隙演变及致密强化规律。探讨了预压Mo坯高径比对压扭Mo坯微观结构及性能的影响。结果表明,高径比越小,材料等效剪切应变量越大,压扭Mo坯相对密度、硬度值越高,其内部亚晶尺寸细化及微观应变积累越明显。当高径比从0.5降至0.3时,由晶粒细化及应变积累引起的位错密度可从1.67×10~(14) m~(-2)提高到3.03×10~(14) m~(-2)。
Using refractory metal pure Mo powder as raw material, a metal Mo blank with a relative density of 96.45% was produced by high-pressure torsion process at a temperature of 350 ° C. and a pressure of 1.5 GPa. Mo powder particle voids Evolve and strengthen the law of density. The effect of pre-compacted ratio of aspect ratio to microstructure and properties of Mo-pressed compact was discussed. The results show that the smaller the height-diameter ratio is, the larger the equivalent shear strain of the material is. The relative density and the higher the hardness value of the material are, the more the internal subgrain size and the micro-strain accumulate. When the aspect ratio is reduced from 0.5 to 0.3, the dislocation density caused by grain refinement and strain accumulation can be increased from 1.67 × 10 ~ (14) m ~ (-2) to 3.03 × 10 ~ (14) m ~ (-2).