A comparison of impression and compression creep behavior of polycrystalline Sn

This paper reports on the application of a miniaturized impression creep test to measure the creep behavior of pure polycrystalline Sn, and compares the results to compression creep data on the same sample, in order to experimentally determine a scaling constant to formulate the equivalent uniaxial creep constitutive law from the impression creep data. The creep parameters determined via impression and compression creep are found to be identical, with n similar to 5 and Q similar to 42 kJ/mol, indicating that over the tested stress-temperature range, the mechanism is core diffusion controlled dislocation creep. In conjunction with results from previous modeling work, a single conversion factor, K-n/C, which depends on material properties, is shown to be usable for converting the impression creep relation to the equivalent uniaxial creep relation, and the experimentally determined value of k(n)/C for polycrystalline Sn is very close to that obtained via modeling.