In-situ Investigation of the Fracture Behaviors of 2195-T8 Aluminum-Lithium alloy

Liang Wang,Min Hao,Guoai Li,Gaohong Chen,M Jawaid,El-R Kenawy

doi:10.1051/matecconf/20166705028

Abstract

In this paper, the tensile crack initiation and propagation behavior of 2195-T8 Aluminum-Lithium alloy was studied by in situ scanning electron microscope observation at room temperature. It was found that cracks initiated at second phases which propagated along the grain boundaries only as T1 phases could retard crack growth inside grains. With further increase of strain, within the grain a large number of slip bands were produced, resulting in the deflection of the grains, which leaded to transgranular fracture at last. SEM examination show both intergranular and transgranular fracture surface morphology indicating that the 2195-T8 alloy revealed a mix mechanism for the fracture.

Highlights

In the aeronautics and space industries, one of the most effective ways to reduce weight is to reduce the density of the aluminum alloys used
In the rolling direction (RD)-transverse direction (TD) plane, original large grains and small equiaxed recrystallized grains were observed in 2195 alloy, while there were large pancake-shaped grains with equiaxed recrystallized grains in the RD-normal direction (ND) and TD-ND planes
It can be concluded that the 2195-T8 alloy revealed a mix mechanism for the fracture, and both intergranular and transgranular fracture surface morphology were observed under the scanning electron microscope (SEM) examination

Summary

Introduction

In the aeronautics and space industries, one of the most effective ways to reduce weight is to reduce the density of the aluminum alloys used. 2195 Aluminum-Lithium alloy is widely used in aerospace and aeronautic ¿elds for its light weight, high speci¿c strength, good ductility and toughness [1,2,3]. The T1 precipitate phase acts as a non shearable barrier to hinder dislocation motion, and is considered to be responsible for the relatively good strength and fracture toughness properties of 2195-T8 when compared to other Al-Li alloys [10,11]. The precipitation of the T1 phase in 2195-T8 will promote homogeneous slip, as opposed to other Al-Li alloys that exhibit localized slip mechanisms. This homogeneous deformation contributes to the increased strength and fracture toughness of this alloy [12]. The microstructure of the fracture surfaces is characterized in an effort to identify the fracture mechanism

Experimental

Results and Discussion

Summary