Hard materials characteristics for the application of micro-forming.

Usually, negligible factors in macro- or miniature size materials such as grain-size effects, may not be neglected in micro-forming processes. Studies had shown that material behaviour varies greatly with the increasing of the scale in the micro-forming world. Therefore, in every micro-forming-related process, especially in micro-stamping, studies and analyses of each material used for the process must be considered as indispensable in order to be able to understand their behaviour and to be able to correlate their behaviour with the process. Uniaxial tensile-testing experiments have been carried out to determine the sheet's properties, behaviour and its correlation with the feeding process in micro-stamping/micro-sheet-forming application. Based on the results of the uniaxial tensile-test experiments conducted, the flow stress was found to decrease with the decrease of the sheet thickness and vice versa, due to the size/scale effect. A surface model was used to explain the findings. It is known that surface roughness has some correlation with friction. Therefore, surface-roughness measurements and the coefficient of friction between contact pairs also have been determined in order to study the correlation between the two quantities. [ABSTRACT FROM AUTHOR]