Effect of Heat Treatment on the Microstructure and Mechanical Properties of the Friction Stir Processed AZ91D Magnesium Alloy

Govindaraju, M.; Vignesh, R. Vaira; Padmanaban, R.

doi:10.1007/s11041-019-00422-1

Cited by 16 publications

(8 citation statements)

References 19 publications

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“…It can be observed that there is an appreciable decrease in the UTS of BM and FSPed specimens, which were heated to 540 °C. This behavior may be attributed to the coarsening of grains and of β-phase (Al 3 Mg 2 ) due to high temperature to which the tensile samples were heated [30]. In addition, a complete dissolution of β-phase at high temperatures and subsequent nucleation of sub-micron β-phases during cooling in air results causes lower tensile strength [31].…”

Section: Effect Of Heat Treatment On Tensile Strengthmentioning

confidence: 99%

Mechanical and microstructural characterization of Ti-SiC reinforced AA5083 surface composites fabricated via friction stir process

Rahman

Khan

Siddiquee

et al. 2021

Mater. Res. Express

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A mixture of Titanium and silicon-carbide powders was embedded in the AA5083 matrix by Friction Stir Processing (FSP). Experiments were performed as per Taguchi L8 orthogonal array, and the effect of reinforcement on hot strength (at 100oC), processed zone (PZ) geometry, and microstructure were investigated. The effect of PZ geometry on the surface properties was also analyzed. The effect of heating the tensile test specimens to 540ºC on the strength at 100oC was also separately investigated. It was observed that surface hardness was significantly enhanced by FSP, and the highest mean hardness of 90.4 HV was observed. Furthermore, it was observed that the surface properties also significantly depend on PZ geometry. From experimental results, it was found that the specimens with the lowest width to depth ratio bears the highest hardness and vice versa. A clear effect of parameters was evident on the geometry of processed zones with a deep bowl, and shallow cup-shaped zones were formed with smaller and larger shoulder diameters, respectively. The samples were processed at 355 rpm, 63 mm/min, 17 mm shoulder, and 355 rpm, 80 mm/min. The 20 mm shoulder showed high tensile strength 292 MPa and 294 Mpa, respectively. The strength of these samples did not reduce much even after heating to 540oC.

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Section: Effect Of Heat Treatment On Tensile Strengthmentioning

confidence: 99%

Mechanical and microstructural characterization of Ti-SiC reinforced AA5083 surface composites fabricated via friction stir process

Rahman

Khan

Siddiquee

et al. 2021

Mater. Res. Express

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“…ey indicated that cast and dissolved samples had cyclic hardening, which can generally be due to increased dislocation density, and the aged samples exhibited nonuniform behavior during microplastic deformation. Govindaraju et al [13] illustrated the effect of heat-treating and FSP on the AZ91D alloy. ey indicated that crack growth at high-stress levels changed from continuous to discontinuous mode under the influence of heat-treating.…”

Section: Introductionmentioning

confidence: 99%

“…As a result of reviewing the literature, researchers have tested many approaches to enhance the mechanical and fatigue properties of magnesium alloy cylinders and cylinder heads such as different types of heat treatment [7][8][9][10][11][12]14,[16][17][18][20][21][22][23], FSP [13], the addition of rare earth elements [4,6,[19][20][21][22][23], the addition of nanoparticles [10,20,24], and so on. In addition, investigation of the HCF properties of heat-treated AZ91 and AZE911 alloys is still rare.…”

Section: Introductionmentioning

confidence: 99%

Effect of Heat-Treating on Microstructure and High Cycle Bending Fatigue Behavior of AZ91 and AZE911 Magnesium Alloys

Oliya

Azadi

Parast

et al. 2022

Advances in Materials Science and Engineering

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This article investigates the influences of heat-treating on the microstructures and the high cycle fatigue (HCF) properties of AZ91 and AZE911 (AZ91 + 1%RE) magnesium alloys. For such an objective, AZ91 and AZE911 alloys were used after solution treatment at 415°C for 5 hours aged at 215°C for 3 hours and at 215°C for 5 hours, respectively. To investigate the HCF behavior, a rotational bending fatigue test was performed with stress ratio (R) −1 and frequency of 100 Hz at room temperature. Optical microscopy (OM) study demonstrates that heat treatment leads to a reduction in grain size and transformation of continuous and discontinuous precipitations into needle-shaped precipitations, which are located on the grains of the alpha phase. Scanning electron microscopy (SEM) showed both marks of quasicleavage and cleavage on the fracture surface of specimens. These planes indicated the brittle behavior of the fracture. Moreover, in heat-treated specimens, the size of cleavage patterns was smaller, and microcracks were shorter. These behaviors affected the strength of the material and the fatigue lifetime. The results of mechanical tests show a negligible influence of heat-treating on the HCF behaviors of AZ91-T6 and AZE911-T6 alloys. Stress-lifetime curves (S-N) show an increase in fatigue strength in 3.8 × 105 fatigue cycles, from 95 MPa to 125 MPa for the AZ91-T6 alloy and from 125 MPa to 155 MPa for the AZE911-T6 alloy, after heat treatment.

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“…Shamsudeen et al [17] demonstrated the influence of tool shape on microstructural properties and tensile strength of AA 5052 H32 aluminum alloy. Govindaraju et al [18] studied the influence of FSP with several heat treatment conditions on the microstructural evolutions of AZ91. They reported coaxial graining and excellent strength after heat treatment.…”

Section: Introductionmentioning

confidence: 99%

Numerical and experimental investigation of defects formation during friction stir processing on AZ91

et al. 2021

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The heat generated during friction stir processing greatly affects defects formation in the processed zone of workpieces. In this paper, numerical modeling of this process is performed to determine the influence of tool rotational and traverse speeds and hence their ratio on the thermal distribution attained during the process. The aim is to produce defect-free processed samples by selecting adequate tool speeds. The mechanisms of defects formation depending on the peak temperature are also investigated. Experiments to verify the simulation results were conducted with the same process parameters. Several traverse speeds of 20, 40, 60, and 80 mm/min and rotational speeds of 700, 1000, 1200, and 2000 rpm were used during modeling and conducting the experiments. From the numerical and experimental results, it was found that; the high-speed processing conditions (low-generated heat) can produce defects such as tunnels and grooves, and the low-speed processing conditions (high-generated heat) can cause defects such as flashes. The experimental results show that during friction stir processing with the rotational speed of 1200 rpm and the traverse speed of 60 mm/min (speed ratio of 20), no macro defects in the processed zone were observed. According to the numerical results, the peak temperature during friction stir processing with these speeds was 475 °C. At this temperature, the material softened, the structure finely equiaxed and no large scale melting zone appeared in the processed zone. The developed model can be useful to investigate the occurrence of defects associated with different tool rotational and traverse speeds. Graphic abstract

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Effect of Heat Treatment on the Microstructure and Mechanical Properties of the Friction Stir Processed AZ91D Magnesium Alloy

Cited by 16 publications

References 19 publications

Mechanical and microstructural characterization of Ti-SiC reinforced AA5083 surface composites fabricated via friction stir process

Mechanical and microstructural characterization of Ti-SiC reinforced AA5083 surface composites fabricated via friction stir process

Effect of Heat-Treating on Microstructure and High Cycle Bending Fatigue Behavior of AZ91 and AZE911 Magnesium Alloys

Numerical and experimental investigation of defects formation during friction stir processing on AZ91

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