Characterization of Al-Li 2099 extrusions and the influence of fiber texture on the anisotropy of static mechanical properties

The development of aluminum-lithium alloys for aerospace applications requires a thorough understanding of how processing and product geometry impact their microstructure, texture and mechanical properties. The anisotropy of the mechanical properties is in part related to the deformation texture formed during thermo-mechanical processing. In this study, two different extrusions of Al-Li 2099 T83 were characterized, a cylindrical extrusion and an integrally stiffened panel (ISP). A decrease of tensile properties was observed from the longitudinal direction to the transverse direction with a minimum in the 45 direction, the magnitude of which depends on the location in the extrusions. The < 111 > fiber texture is prominent in most locations of the extrusion with a smaller intensity of the < 111 > component. Rolling textures were observed in two locations of the ISP that have a larger cross sectional aspect ratio. Variations of strength and anisotropy as a function of location in the extrusion correlate well with the intensity of the < 111 > fiber texture. On the other hand, our findings show an absence of correlation between the Taylor factor and the anisotropy. These results suggest that strength anisotropy may be controlled by the volume fraction of T-1 precipitates that could itself be related to the intensity of the < 111 > fiber texture. (C) 2013 Elsevier B.V. All rights reserved.

用于航空航天应用的铝锂合金的开发需要深入了解加工和产品几何形状如何影响其微观结构、织构和力学性能。力学性能的各向异性部分与热机械加工过程中形成的变形织构有关。在这项研究中，对Al - Li 2099 T83的两种不同挤压件进行了表征，一种是圆柱形挤压件，另一种是整体加强板（ISP）。从纵向到横向观察到拉伸性能下降，在45°方向达到最小值，其程度取决于挤压件中的位置。<111>纤维织构在挤压件的大多数位置都很显著，<111>组分的强度较小。在ISP的两个具有较大横截面纵横比的位置观察到轧制织构。挤压件中强度和各向异性随位置的变化与<111>纤维织构的强度密切相关。另一方面，我们的研究结果表明泰勒因子与各向异性之间没有相关性。这些结果表明，强度各向异性可能由T - 1析出物的体积分数控制，而T - 1析出物本身可能与<111>纤维织构的强度有关。（C）2013爱思唯尔B.V.保留所有权利。