Microstructural evolution and impression creep properties of a lead-based alloy PbSn₁₆Sb₁₆Cu₂

Abstract The impression creep behavior of a lead-based PbSn16Sb16Cu2 alloy was studied at stresses in the range from 15 to 30 MPa and temperatures in the range from 333 to 393 K. XRD, SEM, and EDS techniques were used to analyze microstructural evolutions of the alloy before and after creep at different impression creep conditions. Results show that, in the range of experimental conditions, the calculated stress exponent and the creep activation energy of the alloy are 4.12 and 60.56 kJ mol−1, respectively. Grain boundary diffusion-dominated dislocation climbing is the main impression creep mechanism of PbSn16Sb16Cu2 alloy. Creep rate increases and creep resistance decreases with the increase of temperature and stress, respectively. Two reasons dominate the creep process: first, Sn is largely precipitated from the solid solution in the matrix, which weakens the overall strength of the matrix during the creep process; second, as temperature and stress increase, the atoms are vibrated more fiercely by thermal energy, which results in a softening of the matrix and SnSb phase.