摘要
在工件表面覆盖一层梯度纳米结构提高其硬度、抗疲劳强度、抗腐蚀强度等服役性能,已成为一种重要的表面强化技术。塑性变形是表面梯度纳米结构形成的一种有效途径,而切削加工作为一种典型的塑性变形过程(应变可达13,应变率可达106s-1)满足了这一要求。对国内外相关研究成果进行梳理,从切削加工制备梯度纳米结构的理论基础入手,通过阐明塑性变形-应变、应变率-位错等之间的关系,描述切削过程中切削表面与切屑的微观组织演变,并结合有限元仿真分析和切削加工实验对切削加工过程中制备梯度纳米结构的可行性进行分析。具体阐述了切削制备技术的特点与优势,如缩短工件生产周期,降低生产成本,提高加工效率,拓展加工范围等;提出切削制备梯度纳米结构所面临的一些基础性难题,例如,晶粒细化机理和微观组织演变过程存在争议,切削过程中切削热引起再结晶问题,形成的梯度纳米结构难以达到服役要求等。最后,对切削制备技术发展过程中所要突破的关键技术及未来应用前景进行了展望。
The hardness,fatigue strength and corrosion strength,etc. of workpiece can be significantly increased by covering a layer of gradient nanostructure,which has become one of the important surface strengthening technologies. Plastic deformation is an effective way to form the surface gradient nanostructures,while cutting is a typical plastic deformation process（ strain can reach 13,with a strain rate of up to 106s- 1） meeting this requirement. In this paper,based on the theory of cutting fabrication of gradient nanostructures,the relevant research results were combed by clarifying the relationships between plastic deformation-strain,strain rate-dislocation,and so on,and the microstructure evolution of the cutting surface and cuttings during the cutting process was described. Besides,finite element simulation and cutting experiments were combined to analyze the feasibility of cutting machining process for preparing gradient nanostructures. Then the technical features and advantages of cutting preparation techniques were specifically addressed,such as greatly shortened production cycle of the workpiece,reduced production costs,improved processing efficiency,expanded processing range. Some basic problems faced by cutting machining process for preparation of gradient nanostructures were proposed,for example,controversy in the grain refinement mechanism and microstructure evolution,recrystallization caused by cutting heat,difficulty in meeting service requirements of the formed gradient nanostructures. Finally,the key technology and future prospects of fabrication technology by cutting fabrication were forecasted.
出处
《表面技术》
EI
CAS
CSCD
北大核心
2015年第11期59-65,86,共8页
Surface Technology
基金
国家自然科学基金青年基金(51105172)
山东省自然科学基金(高校联合专项ZR2015EL028)~~
关键词
切削表面
梯度纳米结构
晶粒细化
应变
应变率
塑性变形
服役性能
cutting surface
gradient nanostructure
grain refinement
strain
strain rate
plastic deformation
service performance
