J-integral evaluation of cold worked and aged TiNbSn alloys as a
function of alloy content
Abstract
The present study evaluates the J-integral resulting from cold rolling
and aging treatments applied to TiNbSn alloys comprising different
contents of Nb (35% and 42%) and Sn (0% and 2.5%). The alloys were
arc melted, homogenized, solution heat treated, cold-rolled and aged at
400 °C during different aging times. A set of characterization tests,
including microstructural, scanning electron microscopy, work hardening
coefficients and fracture analysis were performed. The cold worked
alloys with the highest Nb content showed the highest toughness. The
addition of Nb in these alloys is beneficial for toughness since Nb
stabilizes the β phase. In alloys with lower Nb content, cold forming
causes a greater amount of α” and this disfavors toughness. Aging caused
a reduction in the alloys’ toughness, since the formation of
precipitates in aging causes shallower and smaller dimples in the
fracture, corroborating to a lower toughness.