IMPRESSION CREEP OF LEAD

The impression creep behavior of lead was investigated using a 100 mum diameter punch at ambient and elevated temperatures (433 K-563 K) und er punching stresses of 6-70 MPa. The results were compared with the d ata obtained from conventional creep tests reported in the literature. Unlike the indentation creep test, the impression creep test showed a steady-state velocity after a short transient period when the flat-en d cylindrical punch was pushed against the lead surface by a constant load. Both the temperature and stress dependences were comparable to t hose of the constant stress tensile creep tests under similar conditio ns. A master curve for lead was established by collecting data from th e impression creep tests and the constant stress tensile creep tests. The indentation creep measurements for lead were included also. Howeve r, the indentation data depend on the load applied.