摘要
采用超音速微粒轰击技术在38CrSi合金钢表面制备了厚度约为25μm纳米晶层。利用X射线衍射、扫描电镜和透射电镜对表面结构进行分析。纳米结构层的最表面层的晶粒尺寸约为16nm,晶粒尺寸随着距表面距离的增加而增大。利用纳米压痕仪对表面纳米结构层的力学性能进行研究,结果表明,当表面晶粒尺寸降低到纳米量级时力学性能明显改善,最表面纳米结构层的硬度是基体的2倍左右,并服从Hall-Petch关系;表面纳米结构层的弹性恢复系数明显提高;利用该方法制备的纳米晶对弹性模量的影响较小;对表面纳米化样品进行低温退火处理可使纳米结构层的性能更加稳定。分析表明表面纳米结构层力学性能的改善主要是表面晶粒细化的结果。
A nanocrystalline surface layer of about 25 μm thickness was fabricated on a quenched and tempered 38CrSi alloy steel by using supersonic fine particles bombarding（SFPB） technique. The grain size is about 16nm in the top surface layer, and increases with increasing depth from the treated surface. The microstructure of the treated layer was characterized by using SEM, XRD and TEM. The mechanical properties of the surface layer in the SFPBed and original 38CrSi steel samples were measured by means of nanoindentation test. Experiment results show that mechanical properties of the surface layer in the SFPBed sample are improved along with grain refined to nanoscale. The hardness of the top nanocrystalline layer is about 2 times of that of the matrix, and hardness increases almost linearly with d ^-1/2 （ d is diameter of grain） and the result conform to Hall-Petch relation. The elastic recovery parameter in the nanostructured layer is increased evidently. The elastic modulus of the surface layers on the SFPBed sample varies slightly compared with original sample. Low-temperature annealing the structure and property of nanostructured surface layer uniform and stable. The improvement of mechanical properties of the SFPBed layer is primarily attributed to the grain refinement.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2007年第5期115-119,共5页
Transactions of Materials and Heat Treatment
基金
装备维修科研资助项目(2004.1541)
关键词
表面纳米化
纳米结构层
38CrSi钢
力学性能
surface nanocrystallization
nanostructured surface layer
38CrSi steel
mechanical properties
