The Influences of Size Effects on Material Hardness and Interface Friction
Date Issued
2004
Date
2004
Author(s)
Tsai, Chia-Wen
DOI
zh-TW
Abstract
Microforming is an important technology in the development of industry. When the product is getting smaller, the so-called size-effect makes the material properties changes and the friction characteristics different with it in convenient works. A lot of properties we neglect in convenient working will become effective in microforming process. However, the smaller the material is, the harder in measuring the mechanic properties. Besides, we can know that the hardness has some specific relations with the flow stress. The present study uses the theory of similarity to design experiences. Observe the compression stress in different scale material and use microhardness to analyze the effect in flow stress and hardness by size-effect. Trying to find the hardness-strain curve and compare with the stress-strain curve. Analyze the applicability of adjusting the measuring of stress-strain curve in small materials by hardness test. Finally, analyze the lubrication properties and formability change with the size of grain and die using a forward-backward extrusion process.
Subjects
精微成形
應力應變曲線
錐杯擠形
微硬度
有限元素法
microforming
stress-strain curve
micro-indentati
Type
thesis