Age hardening and its modeling of Ti–2.5Cualloy

Age hardening behavior and relevant strengthening mechanisms of Ti–2.5Cu alloy have been investigated in detail. A transmission electron microscope (TEM) was used to investigate the microstructures of solution treated and two-stage aged Ti-2.5Cu specimens. It was observed that, Ti2Cu plates with three variants appeared in {11¯00} planes of α-Ti grains. The Orowan increment in critical resolved shear stress (CRSS) produced by the need for dislocations to by-pass Ti2Cu plates in three kinds of slip plane, i.e., {11¯00}, {0001} and {11¯01}, was analyzed respectively in detail. Based on these analyses, a strength model of aged Ti-2.5Cu alloy was established incorporating Orowan strengthening and solution strengthening mechanisms. The calculation results of this model met well with the measured values.