【摘要】 以高能球磨法和等离子体蒸发法制备的纳米晶镍粉为原料,采用预压烧结法制备了块体纳米晶镍。采用XRD、SEM和自动压汞仪对试样的微观组织结构及孔隙率进行检测,对其硬度、压缩强度进行测试。结果表明:由于等离子体蒸发法制备的纳米晶镍粉为均匀、细小的球状晶粒,具有较小的微观应变,从而比球磨试样更易于成型,块体的致密度更高,热稳定性更好。等离子体蒸发试样的硬度较高,压缩屈服强度达310~410 MPa,表现出较低的加工硬化和良好的塑性压缩形变能力,断口为沿晶断裂,晶界滑移在变形中起到重要作用。更多还原

【Abstract】 The nanocrystalline nickel powder prepared by high energy ball milling(HEBM)and arc plasma evaporation(APE) method was consolidated into bulk specimens by pre-press sintering.The microstructure,porosity,hardness and compression strength of the bulk nanocrystalline nickel prepared by different methods were investigated.The results show that the evaporated bulk nanocrystalline nickel samples are easier to shape,and have higher density and thermal stability compared to the milled nickel samples because of evaporated nanocrystalline nickel powder is uniform,fine,globular and has small micro strain.The hardness of the evaporated bulk nanocrystalline nickel is higher and the compression yield strength ranging from 310 MPa to 410 MPa,the specimen exhibits lower sensitivity to strain rate and lower working hardening exponent.The damage mechanism of the evaporated bulk nanocrystalline nickel is intergranular fracture and grain boundary sliding mechanism plays an important role on the plastic deformation of the specimen.更多还原