EBSD Study of Delamination Fracture in Al–Li Alloy 2090

Abstract

Aluminum-lithium (Al-Li) alloys offer attractive combinations of high strength and low density for aerospace structural applications. However, a tendency for delamination fracture has limited their use. Identification of the metallurgical mechanisms controlling delamination may suggest processing modifications to minimize the occurrence of this mode of fracture. In the current study of Al-Li alloy 2090 plate, high quality electron backscattered diffraction (EBSD) information has been used to evaluate grain boundary types exhibiting delamination fracture and characterize microtexture variations between surrounding grains. Delamination was frequently observed to occur between variants of the brass texture component, along near-Σ3, incoherent twin boundaries. EBSD analyses indicated a tendency for intense deformation along one side of the fractured boundary. A through-thickness plot of grain-specific Taylor factors showed that delaminations occurred along boundaries with the greatest difference in Taylor factors. Together, these suggest a lack of slip accommodation across the boundary, which promotes significantly higher deformation in one grain, and stress concentrations that result in delamination fracture.

Micro-grinding temperature prediction considering the effects of crystallographic orientation

“…The texture micrographs of the four samples are shown in Figure 2. [25] In the paper, CO is represented by Miller indices [27], which are used to indicate directions and planes of crystals. Miller indices form a notation system in crystal: [uvw] and ⟨uvw⟩ specify a direction and a family of directions, respectively, (hkl) and {hkl} represent a plane and a family of planes, respectively.…”

Forces prediction in micro-grinding single-crystal copper considering the crystallographic orientation

“…In the investigation, six cutting directions were chosen with two crystal directions of each sample tested using EBSD, as shown in Figure 2. In the investigation, CO is presented by Miller indices [24]. For example, [h k l] is parallel to the grinding direction, while (u v w) is perpendicular to the grinding plane.…”

Dynamic Mechanical Behavior and Hypervelocity Impact Performance of an Al-Based Nanocrystalline Alloy

“…The Taylor factor (M) was next examined. For the facecentered cubic (fcc) polycrystal of the 2219 aluminum alloy, the {111}\110[ slip systems were dominant and were considered for the M calculations [19]. The larger values of M denote orientations that are more resistant to plastic deformation under a specified strain path [9].…”