论文部分内容阅读
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。
Nanocrystalline nickel powder prepared by high-energy ball milling method and plasma evaporation method was used as raw material. The microstructure and porosity of the samples were measured by XRD, SEM and mercury porosimetry. The hardness and compressive strength of the samples were tested. The results show that the nanocrystalline nickel powders prepared by plasma evaporation are uniform and fine spherical grains with small micro-strain, which makes them easier to shape than the ball-milled samples with higher bulk density and thermal stability better. The hardness of plasma evaporation sample is higher, the compressive yield strength reaches 310-410 MPa, showing lower work hardening and good plastic compressive and deformability. The fracture is intergranular fracture, and grain boundary slip plays an important role in the deformation effect.