CAJ | 학술논문

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106 s-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.
재공건표면복개일층제도납미결구제고기경도、항피로강도、항부식강도등복역성능,이성위일충중요적표면강화기술. 소성변형시표면제도납미결구형성적일충유효도경,이절삭가공작위일충전형적소성변형과정(응변가체13,응변솔가체106 s-1 )만족료저일요구. 대국내외상관연구성과진행소리,종절삭가공제비제도납미결구적이론기출입수,통과천명소성변형-응변、응변솔-위착등지간적관계,묘술절삭과정중절삭표면여절설적미관조직연변,병결합유한원방진분석화절삭가공실험대절삭가공과정중제비제도납미결구적가행성진행분석. 구체천술료절삭제비기술적특점여우세,여축단공건생산주기,강저생산성본,제고가공효솔,탁전가공범위등;제출절삭제비제도납미결구소면림적일사기출성난제,례여,정립세화궤리화미관조직연변과정존재쟁의,절삭과정중절삭열인기재결정문제,형성적제도납미결구난이체도복역요구등. 최후,대절삭제비기술발전과정중소요돌파적관건기술급미래응용전경진행료전망.
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 106 s-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 de- scribed. 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 nano-structures were proposed, for example, controversy in the grain refinement mechanism and microstructure evolution, recrystalliza-tion caused by cutting heat, difficulty in meeting service requirements of the formed gradient nanostructures. Finally, the key tech-nology and future prospects of fabrication technology by cutting fabrication were forecasted.