Effects of cold pre-forging on microstructure and tensile properties of extruded AZ80 alloy

Kim, Ye Jin; Kim, Sang-Hoon; Lee, Jong Un; Choi, Jae Ok; Kim, Ha Sik; Kim, Young Min; Kim, Yong-Jin; Park, Sung Hyuk

doi:10.1016/j.msea.2017.09.124

Cited by 30 publications

(8 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The hot extrusion process has become a promising method, which can be optimized for grain refinement by adjusting extrusion ratio, pressing temperature, and ram speed . Several studies on different types of extrusion process for Mg alloys including the asymmetric extrusion, back extrusion, compound extrusion, lateral extrusion, extrusion with artificial cooling, and extrusion followed by pre‐forging have been reported recently. In fact, a great deal of works is available on microstructure and texture evolution of Mg alloys during hot extrusion process …”

Section: Introductionmentioning

confidence: 99%

Enhanced Ductility of a Fine‐Grained Mg–Gd–Al–Zn Magnesium Alloy by Hot Extrusion

et al. 2018

View full text Add to dashboard Cite

The grain refinement by dynamic recrystallization (DRX), the enhancement of room-temperature strength and ductility by decreasing hot extrusion temperature, and the effect of grain growth at elevated temperatures are discussed for a newly developed as-cast Mg-Gd-Al-Zn magnesium alloy. The results are supported by fracture surface observations, texture analysis by Schulz reflection method based on X-ray diffraction (XRD), and work-hardening rate plots. It is found that by decreasing the extrusion temperature, the ductility of alloys enhances, which is related to the weakening of basal texture by the rare earth element Gd. Moreover, the grain growth annealing resulted in decreasing the strength and increasing the ductility in the conventional manner, where the texture intensity remained unchanged.

show abstract

Section: Introductionmentioning

confidence: 99%

Enhanced Ductility of a Fine‐Grained Mg–Gd–Al–Zn Magnesium Alloy by Hot Extrusion

et al. 2018

View full text Add to dashboard Cite

show abstract

“…On the other hand, the work hardening capacity of Mg alloy increases due to the addition of Y-element. This can be illustrated using the Hollomon equation [34] as follows: S = Ke n (1) where S is the true stress, e is the true strain, n is the strain hardening exponent, and K is the work hardening coefficient, respectively. The strain hardening exponent (n) increases with the decrease of stacking fault energy.…”

Section: Discussionmentioning

confidence: 99%

“…S=Ke n (1) where S is the true stress, e is the true strain, n is the strain hardening exponent, and K is the work hardening coefficient, respectively. The strain hardening exponent (n) increases with the decrease of stacking fault energy.…”

Section: Strengthening Mechanism Of the Isothermal Forging Processmentioning

confidence: 99%

“…As the crisis of resource and environment become more and more intensive, the requirement for energy conservation and emission reduction in transportation vehicles is growing insistently [1,2]. Mg, as a promising material, has attracted more attention due to its high specific strength, low density, good recyclability, and low cost [3][4][5].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Preparation and Mechanical Properties of ZK61-Y Magnesium Alloy Wheel Hub via Liquid Forging—Isothermal Forging Process

Heng

Chen

et al. 2020

Metals

View full text Add to dashboard Cite

A ZK61-Y magnesium (Mg) alloy wheel hub was prepared via liquid forging-isothermal forging process. The effects of Y-element contents on the microstructure and mechanical properties of liquid forging blanks were investigated. The formation order of the second phase was I-phase (Mg 3 Zn 6 Y) → W-phase (Mg 3 Zn 3 Y 2 ) → Z-phase (Mg 12 ZnY) with the increase of the Y-element content. Meanwhile, the I-phase and Z-phase formed in the liquid forging process were beneficial to the grain refinement. The numerical simulation of the isothermal forging process was carried out to analyze the effects of forming temperature on the temperature and stress field in the forming parts using the software Deform-3D. Isothermal forging experiments and post heat treatments were conducted. The influence of isothermal forging temperature, heat treatment temperature and preservation time on the microstructure and mechanical properties of the forming parts were also studied. The dynamic recrystallization (DRX), second-phase hardening, and work hardening account for the improvement of properties after the isothermal forging process. The forming part forged at 380 • C displayed the outstanding properties. The elongation, yield strength, and ultimate tensile strength were 18.5%, 150 MPa and 315 MPa, respectively. The samples displayed an increased elongation and decreased strength after heat treatments. The 520 • C-1 h sample possessed the best mechanical properties, the elongation was 25.5%, the yield stress was 125 MPa and the ultimate tensile strength was 282 MPa. This can be ascribed to the recrystallization and the elimination of working hardening. Meanwhile, the second phase transformation (I-phase → W-phase → Mg 2 Y + MgZn 2 ), dissolution, and decomposition can be observed, as well.Mg-Zn-Y LPSO phases with Zn, Y-rich compositions prepared and investigated the crystal structures of the 18R-, 14H-, and 10H-type Mg-Zn-Y LPSO/OD phases with the perfect in-plane order of the Zn 6 Y 8 atomic clusters identical to that of the Mg-Al-Gd LPSO/OD phases. Takagi et al. [12] performed micro-double-shear tests in the temperature range of 298 K-673 K to quantify the temperature dependence of prismatic slip in a long-period stacking ordered Mg 85 Zn 6 Y 9 . They found that the prismatic slips were promoted through cross-slip onto the basal plane over the transition temperature. Mahmudi et al. [13] examined the effects of adding 2 wt % yttrium (Y) element on the thermal stability, microstructural evolution, and mechanical properties of an Mg-4Zn alloy. Addition of yttrium led to simultaneous refinement of the microstructure and improvement in both shear strength and microstructural stability of Mg-4Zn at high temperature. The addition of yttrium (Y) facilitates the formation of the I-phase (Mg 3 Zn 6 Y), W-phase (Mg 3 Zn 3 Y 2 ), and Z-phase (Mg 12 ZnY) [14]. The I-phase with octahedron quasicrystal structure forms at the grain boundary, which is detrimental to the alloy properties [15,16]. However, the I-phase with quasicrystal structure facilitate...

show abstract

“…Clearly, the cold deformation method can be a significant supplement to the above-mentioned methods. Particularly, some simple cold deformation ways with low cost (e.g., uniaxial tension/compression [22,33,34,35,36], free-end torsion [27], low-strain rolling/forging [26,37,38,39,40], etc.) have exhibited a great application potential in the regulation of precipitates.…”

Section: Introductionmentioning

confidence: 99%

Regulating Precipitates by Simple Cold Deformations to Strengthen Mg Alloys: A Review

et al. 2019

View full text Add to dashboard Cite

Regulating precipitates is still an important issue in the development of high-strength Mg alloys, due to it determining the precipitation hardening effect. Cold deformation, as a simple and low-cost method, can remarkably influence the precipitate features. It is found that pre-cold deformation before aging can be utilized to enhance the precipitation hardening effect of Mg alloys. Moreover, post-deformation after aging could be an effective method to regulate precipitation orientation. In this review, recent research on the regulation of precipitation behavior by cold deformation in Mg-Al, Mg-Zn, and Mg-RE (RE: rare-earth elements) alloy systems was critically reviewed. The changes in precipitate features and mechanical properties of peak-aged Mg alloys via cold deformation were summarized. The corresponding strengthening mechanisms were also discussed. Finally, further research directions in this field were proposed.

show abstract

Effects of cold pre-forging on microstructure and tensile properties of extruded AZ80 alloy

Cited by 30 publications

References 40 publications

Enhanced Ductility of a Fine‐Grained Mg–Gd–Al–Zn Magnesium Alloy by Hot Extrusion

Enhanced Ductility of a Fine‐Grained Mg–Gd–Al–Zn Magnesium Alloy by Hot Extrusion

Preparation and Mechanical Properties of ZK61-Y Magnesium Alloy Wheel Hub via Liquid Forging—Isothermal Forging Process

Regulating Precipitates by Simple Cold Deformations to Strengthen Mg Alloys: A Review

Contact Info

Product

Resources

About