Analysis of the Deformation Behavior in Tension and Tension-Creep of Ti-3Al-2.5V (wt pct) at 296 K and 728 K (23 A degrees C and 455 A degrees C) Using In Situ SEM Experiments

作者：Li Hongmei^*; Boehlert Carl J; Bieler Thomas R; Crimp Martin A

来源：Metallurgical and Materials Transactions A-Physical Metallurgy and Materials Science, 2014, 45A(13): 6053-6066.

DOI：10.1007/s11661-014-2576-7

The deformation behavior of a Ti-3Al-2.5V (wt pct) near-alpha alloy was investigated during in situ deformation inside a scanning electron microscopy (SEM). Two plates with distinct textures were examined. Tensile experiments were performed at 296 K and 728 K (455 A degrees C) (similar to 0.4T (m)), while a tensile-creep experiment was performed at 728 K (455 A degrees C) and 180 MPa (sigma/sigma (ys) = 0.72). The active deformation systems were identified in the alpha phase using electron backscattered diffraction based slip-trace analysis and SEM images of the surface. Prismatic slip deformation was the dominant slip mode observed for all the experiments in both plates, which was supported by a critical resolved shear stress (CRSS) ratio analysis. However, due to the texture of plate 1, which strongly favored the activation of prismatic slip, the percentages of prismatic slip activity for specimens from plate 1 tested at 296 K and 728 K (23 A degrees C and 455 A degrees C) were higher than the specimens from plate 2 under the same testing conditions. T1 twinning was an active deformation mode at both 296 K and 728 K (23 A degrees C and 455 A degrees C), but the extent of twinning activity decreased with increased temperature. T1 twinning was more frequently observed in specimens from plate 2, which exhibited a higher fraction of twinning systems favoring activation at both 296 K and 728 K (23 A degrees C and 455 A degrees C). The tension-creep experiment revealed less slip and more grain boundary sliding than in the higher strain rate tensile experiments.

• 出版日期2014-12