Wear behavior of sub-microcrystalline metals produced by severe plastic deformation

2015 Fiscal Year Final Research Report

• Project/Area Number: 25420102
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Design engineering/Machine functional elements/Tribology
• Research Institution: Fukui National College of Technology
• Principal Investigator: Kato Hirotaka 福井工業高等専門学校, 機械工学科, 教授 (30311020)
• Co-Investigator(Renkei-kenkyūsha): YASUMARU Naoki 福井工業高等専門学校, 機械工学科, 教授 (90158006) ; TODAKA Yoshikazu 豊橋技術科学大学, 機械工学系, 准教授 (50345956)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 超強加工 / 微細結晶粒材料 / バルクナノメタル / 高圧ねじり加工 / トライボロジー / 摩耗変質層 / 耐摩耗性

Outline of Final Research Achievements

Sliding wear behavior of sub-microcrystalline pure iron discs produced by high-pressure torsion (HPT) straining was studied using a ball-on-disc configuration against a cemented carbide (WC-Co) counter body. The effects of the strain in the HPT process and the duration of wear tests were investigated, and the surface morphology, subsurface microstructure and hardness of the specimens were examined. The degree of wear in the discs decreased considerably with increasing number of turns during HPT, and the wear resistance of pure iron was significantly improved by HPT straining owing to the high hardness of HPT-processed iron. The specific wear rate was inversely proportional to the Vickers hardness of the discs. This study is the first to show that submicron grains produced by HPT straining were further refined to a size of 100-150 nm by friction shear straining beneath the worn surface while grain refinement of iron is saturated upon further straining in HPT processing.

Free Research Field

トライボロジー