Effect of Aging Temperature on the Microstructure and Mechanical Properties of a Novel β Titanium Alloy

Abstract

High-strength metastable β titanium alloys are promising structural materials to be used in aviation industries. In order to achieve a high strength level, solid solution treatment within β region and subsequent low-temperature aging are usually necessary to obtain fine α precipitates. The selection of the aging temperature is considered critical to the mechanical performance of metastable β titanium alloys. In this work, we investigated the effect of aging temperature on the microscopic structure and mechanical properties of a novel type of titanium alloy TB18 (Ti-4.5Al-5Mo-5V-6Cr-1Nb). A series of aging treatments were conducted on TB18 specimens at 510 °C, 520 °C, 530 °C, and 540 °C after the solid solution treatment at 870 °C. On the basis of the systematic results of scanning electron microscope and transmission electron microscope, the behavior of the α phases affected by the varied aging temperatures were studied. As the aging temperature rose, the grain width of the α phase increased from 60 nm (510 °C) to 140 nm (540 °C). For the TB18 samples aged at 510 °C and 540 °C, the tensile strength/yield strength/impact toughness values were 1365 ± 3 MPa/1260 ± 0.9 MPa/26.5 ± 1.2 J/cm2 and 1240 ± 0.9 MPa/1138 ± 0.8 MPa/36.2 ± 1.3 J/cm2, respectively. As a result, the tensile performance and the grain width of the α phase agreed well with the Hall–Petch relationship. This work offers valuable support for both theoretical analyses and the heat treatment strategies on the novel TB18 titanium alloy.

Aging Treatment Induces the Preferential Crystallographic Orientation of αs in the Near-α Titanium Alloy Ti60

“…Solid-solution and aging treatments are extensively employed as strengthening methods for titanium alloys. These methods aim to regulate the microstructure morphology and enhance mechanical properties by exploiting the microstructure's sensitivity to heat treatment conditions [13][14][15]. Indeed, the heat treatment of titanium alloys leads to a complex evolution in microstructure.…”

“…Twelve possible α variants generated during βto α-phase transformation through the BOR[29]. ][11][12][13][14][15][16][17][18][19][20] 60.83• /[−1.377 −1 2.377 0.359] V7 (110) (0001) [1-11] [11-20] 90 • /[1 −2.38 1.38 0] V8 (10-1) (0001) [1-11] [11-20] 60.83 • /[−1.377 −1 2.377 0.359] V9 (011) (0001) [1-11] [11-20] 63.26 • /[−10 5 • /[−1.377 −1 2.377 0.359]…”