Hot Deformation Behavior Of Cu-Fe-P Alloy High Temperature

Cu-Fe-P copper alloys were widely used as lead frames in 1C packages for their good electrical and thermal conductivity and low cost. Hot rolling is the key process. Now controlled rolling, which is combined with hot rolling solution heat treatment by controlled cooling on-line equipped with water treatment system, is an advanced process in manufacturing Cu-Fe-P copper alloys strips. In this present, the hot deformation behaviors of two different Cu-Fe-P alloys (KFC alloy and C194 alloy) were studied by means of compression deformation tests on Gleeble 1500 machine at strain rates ranged between 0.01-lOs"1 and deformation temperature 650-850癈,and associated structural changes were studied by observations of metallographic and TEM. The results are shown as following:1) For C194 alloy, the true stress- true strain curves exhibit a peak stress in the initial stage of deformation, after which the flow stress decreased monotonically. For KFC alloy, the true stress- true strain curves are characterized by multiple peaks or a single peak flow. They tend to or enter a steady state at high strains.2) Maximum stress for C194 alloy can be represented by the exponent-type equation with the activation energy of 316 kJ/mol , and maximum stress for KFC alloy can be represented by a Zener-Hollomon parameter in the hyperbolic-sine-type equation with the hot deformation activation energy Q of 289 kJ/mol.3) A tentative conclusion is that particles in Cu-Fe-P alloys distinctly change theactivation energy, which can be approximately expressed as Q - 304.7 +10.8 In ΣC,,hence increases the flow stress value during hot deformation.4) The DRX grain size of C194 alloy and KFC alloy at high strains is dependent sensitively on deformation temperature T or strain rate ε and also is a function of Z. Increasing of Z leads to a reduction in DRX grain size evolved at high strain. The mechanisms of DRX nucleation appear likely that grain boundary bulging plays a similar role. The DRX substructure is heterogeneous and the DRX grains structure can be classified into the following three categories: i) the DRX nuclei, ii) the growing DRX grains, and iii) the critically work-hardened DRX grain. Under the same deformation condition, a little amount with finer grain size of precipitates were observed in KFC alloy comparing to C194 alloy leads to decrease of flow stress value.5) The strain localization at high strain leads to dynamic precipitation and successive dynamic particles coarsening has been assumed to be responsible for further flow softening, and this is more effective when samples deformed at higher temperatures and low strain rates.