Tian Baohong

Effect of Fe particle on the surface peeling in Cu−Fe−P lead frame

Under the surface peeling of Cu−Fe−P lead frame alloy larger Fe particles were observed by energy dispersive spectroscopy. By using the large strain two-dimension plane strain model and elastic-plastic finite element method, the cause for peeling damage of Cu−Fe−P lead frame alloy was investigated. The results show that when the content of Fe particles is more than 30% at local Fe-rich area the intense stress concentration in the Fe particle would make the Fe particle broken up. The high equivalent stress mutation and the mismatch of equivalent strain 10% at the two sides of interface make it easy to develop to crack and peeling damage on finish rolling. The larger Fe particles in the Cu−Fe−P alloy should be avoided.

Kinetics of internal oxidation of Cu−Al alloy plate

The kinetics of internal oxidation of dilute Cu−Al alloys, containing up to 2.214% molar fraction Al, was investigated over the temperature range of 1023 K to 1273 K, and the depth of internal oxidation was measured by microscopies. A modified rate equation was derived to describe the kinetics of internal oxidation of Cu−Al alloy plate. Based on the derived equation, the permeability of oxygen in solid copper was obtained from the internal oxidation measurements. The experimental results show that the depth of the internal oxidation is a parabolic function of time, there is no evidence for preferential diffusion along grain boundaries and an outer layer of pure copper was formed on the external surface of samples.