Development of an ultrahard nanotwinned cBN micro tool for cutting hardened steel  

作　　者：CHEN Jun Yun JIN Tian Ye TIAN Yong Jun 

机构地区：[1]College of Vehicles and Energy, Yanshan University [2]College of Mechanical Engineering, Yanshan University [3]State Key Laboratory of Metastable Materials Science & Technology, Yanshan University

出　　处：《Science China(Technological Sciences)》2016年第6期876-881,共6页中国科学（技术科学英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.51205343,51332005&51421091);Hebei Provincial Science Foundation of China(Grant No.E2016203372)

摘　　要：Binderless nanotwinned cubic boron nitride(nt-cBN) synthesized from onion-structured BN precursors under high pressure and high temperature shows a very fine microstructure consisting of densely lamellar nanotwins(average thickness of 4 nm) within nanograins. The unique nanotwinned microstructure offers high hardness, wear resistance, fracture toughness, and thermal stability which are essential for advanced cBN tool materials. Thus, a circular micro tool of nt-cBN was fabricated using femtosecond laser contour machining followed by focused ion beam precision milling. Thereafter turning tests were performed on hardened steel using the studied micro tool. To evaluate the cutting performance, the machined surface quality and subsurface damage of the hardened steel were characterized. The wear mechanism of the nt-cBN micro tool was also investigated. It is found that the fabricated nt-cBN micro tool can generate high quality surface with surface roughness less than 7 nm and nanograin subsurface of about 500 nm deep. In addition, abrasive wear is found to be the dominant wear mechanism of the nt-cBN micro tool in turning hardened steel. These results indicate that nt-cBN has outstanding potential for ultra-precision cutting hardened steel.

关 键 词：nanotwinned cBN tool fabrication cutting tool micro machining hardened steel 

分 类 号：TG142[一般工业技术—材料科学与工程]