Tensile tests on a FeNi-base austenitic alloy were conducted at room temperature and 400C, when serrated flow did not and did occur, respectively. Deformation microstructures such as topographies of slip bands, morphologies of twin boundaries and arrangements of dislocations near twin boundaries, as well as concentrations of strain were investigated. It was shown that twin boundaries block slip bands and induce remarkable stress accumulations at 400C. The effect of twin boundary density on the serrated flow was also investigated by comparative tensile tests on specimens with different twin boundary densities at 400C. Details of tensile curves revealed that more twin boundaries induce more pronounced serrations. Therefore, interaction between twin boundaries and slip bands was proposed to induce the serrated flow of the FeNi-base alloy at 400C.

Serrated Flow Induced by Twin Boundary-Slip Band Interactions in a FeNi-Base Austenitic Alloy. S.Zhao, X.Li, L.Rong: Materials Letters, 2011, 65[15-16], 2388-90