Tensile and fatigue behaviour of as-forged AZ31B extrusion

Abstract

Tensile and stress controlled fatigue tests were performed to investigate the influence of forging at a temperature of 400°C at different rates, on the performance of extruded AZ31B magnesium alloy. The obtained microstructural analysis showed that the extruded AZ31B magnesium alloy possesses a bimodal grain structure with strong basal texture. In contrast, the forged samples showed refined grains and a weaker texture. During tensile testing, a maximum yield and ultimate tensile strength of about 163 MPa and 268 MPa were obtained for the forged samples showing an increase of 102% and 7%, respectively from the as-extruded material. At the same time, a significant improvement of fatigue life was also observed for the sample forged at the rate of 100 mm/min. The fractographic analysis of the fracture surfaces showed that ductile type fractures occurred in both as-extruded and forged samples. However, more dimples and plastic deformation were identified in the fracture surfaces of the forged specimens. It is believed that forging improved the fatigue life by a combination of grain refinement and texture modification resulting in improved yield and ductility.

Monotonic and cyclic behaviour of cast and cast-forged AZ80 Mg

“…it is clear that the c-axis orientation of the forged material is coincident with the forging direction; similar reorientation of the c-axis due to forging has been reported by several researchers [40]- [42]. Previous work by Gryguc et al [43] on axially and radially forged AZ31B extruded billets show an analogous caxis reorientation in extruded AZ31 following forging. The effect of forging on the initial random texture is a local reorientation of newly recrystallized grains, causing their crystal axis to align with the forging axis as the deformation progresses.…”

“…Based upon the hardening responses seen in forged conditions S1, S2, and S3, and the strong basal texture shown in Figure 2(d), (g), and (h) the deformation mechanism in tension is dominated by basal slip (as the direction of loading is parallel to the basal plane), and the deformation in compression is dominated by twinning (extension twinning activated via extension along the c-axis). This sigmoidal behaviour, characterized by three distinct hardening stages, has been discussed by other researchers [49] [43].…”

Microstructure, texture and mechanical behavior characterization of hot forged cast ZK60 magnesium alloy

“…Forging is an efficient technique, in which the structural parts are produced in a near net shape [21]. Because of its promise as an effective manufacturing method for Mg alloy microstructure refinement and mechanical property improvement, forging is currently of significant interest for industrial applications [22,23].…”

Mg-Alloys for Forging Applications—A Review

“…Gryguc et al analyzed the compressive [68] as well as the tensile and fatigue behavior [69] of extruded and forged AZ31.…”