The onset of plastic flow in copper materials used for rigid and flexible PCB

Abstract

The study focused on the onset of plastic flow in various copper raw materials. The tested copper sheets varied by the way they were manufactured (e.g. electroplated, cold rolled), by post treatments (e.g. chromate coating) or by pre ageing. Tests were conducted at different temperatures (25°C, 60°C, 100°C, 150°C). The results show that the onset of plastic flow depends strongly on the manufacturing condition of the copper materials. Microstructural investigations were carried out in order to correlate the particular mechanical behaviour with established knowledge about copper as a fcc material. The paper will point out how certain properties of the copper sheets relate to the onset of plastic flow.