Flow stress and tribology size effects in scaled down cylinder compression
(1. School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China;
2. Key Laboratory of Micro-Systems and Micro-Structures Manufacturing, Ministry of Education,
Harbin Institute of Technology, Harbin 150080, China)
2. Key Laboratory of Micro-Systems and Micro-Structures Manufacturing, Ministry of Education,
Harbin Institute of Technology, Harbin 150080, China)
Abstract: Microforming is an effective method to manufacture small metal parts. However, macro forming can not be transferred to microforming directly because of size effects. Flow stress and tribology size effects were studied. Scaled down copper T2 cylinder compression was carried out with the lubrication of castor oil and without lubrication. The results show that the flow stress decreases with decreasing the initial specimen diameter in both lubrication conditions, and the flow stress decreases by 30 MPa with the initial specimen diameter decreasing from 8 mm to 1 mm. The friction factor increases obviously with decreasing the initial specimen diameter in the case of lubricating with castor oil, and the friction factor increases by 0.11 with the initial specimen diameter decreasing from 8 mm to 1 mm. However, the tribology size effect is not found in the case without lubrication. The reasons of the flow stress and tribology size effects were also discussed.
Key words: microforming; size effects; flow stress; friction factor; cylinder compression