Study of grain boundary strengthening, plastic anisotropy and fracturing observations in textured aluminum-lithium 2090-T8E41 alloy

Grain boundary strengthening and crystallographic texture influences have been investigated in conventional plate Al-Li 2090 T8E41 material and related alloys so as to obtain a better understanding of the anisotropic plastic deformation and cracking behavior. That certain grain boundaries are relatively strong barriers to dislocation slip penetrations is demonstrated through the observation of grain boundary protrusions at the circumferential edges of R;Hall-Petch results (;An evaluation of the combined crystallographic texture, grain size, and grain shape influences on the anisotropy of macrohardness indentation shapes and different yield strengths in different planes and directions for Al-Li 2090 T8E41 alloy leads to the conclusion that dislocation pile-ups in slip band stress concentrations make a significant contribution to the measured plastic anisotropy of this specific alloy. Different dislocation pile-up geometries are shown to apply for the effective changed shape of grains around the circumference of elliptical Rockwell R;Stress-strain curves have been obtained for four point bend specimens aligned in different directions of the 2090 T8E41 plate material. The 2090 elastic moduli, though showing greater variation than for aluminum, are not strongly anisotropic, say, much less so than for iron and steel.;Grain orientations within the layered microstructure of elongated thin flat grains were determined via backscattered Kikuchi diffraction patterns. The results compared favorably with reported x-ray pole figures. In general, the components of the rolling texture are a combination of ideal brass, copper, and symmetric (S) elements that are strongest at the mid-thickness of the plate while the cube component associated with a recrystallization texture is strongest at the plate surfaces.;Short length edge compression tests were designed for the purpose of determining grain orientations through slip traces on two adjacent surfaces, especially in relation to induced cracking behavior of the 2090 T8E41 alloy. (Abstract shortened by UMI.).