Effect of cold pre-forging on the microstructure and mechanical properties of extruded Mg–8Sn–1Al–1Zn alloy

Park, Sung Hyuk; Lee, Jeong Hun; Yu, Hui; Yoon, Jonghun; You, Bong Sun

doi:10.1016/j.msea.2014.06.053

Cited by 35 publications

(17 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…9 Additionally, alloying elements such as Zn and/or Al have been proved to be effective in improving mechanical properties by grain refinement and precipitation hardening. 10,11 Recently, Kim et al 12 have reported that an Mg 47.2 Zn 36.9 Al 15.9 icosahedral quasicrystal phase (I-phase) could be obtained by selecting a suitable Zn/Al mass ratio in the Mg-Sn alloy system. The I-phase was solubilized in a-Mg after homogenization and would reprecipitate during the subsequent hot deformation process, resulting in a significant increase in strength.…”

Section: Introductionmentioning

confidence: 99%

Microstructures and mechanical properties of as-ECAPed Mg–8Sn alloys with the combined addition of Zn and Al

et al. 2017

View full text Add to dashboard Cite

A "RE-free" and I-phase-containing Mg-8Sn-based alloy system was developed and successfully fabricated through the equal channel angular pressing (ECAP) process. The influence of the Zn/Al mass ratio on the microstructures and mechanical properties of the as-ECAPed Mg-8Sn-(5,6,7) Zn-2(wt%)Al alloys was investigated using an optical microscope, an X-ray diffractometer, a scanning electron microscope, a transmission electron microscope, and a universal testing machine. Grain size, dynamic recrystallization behavior, and texture were found to be greatly affected by the Zn/Al mass ratio. Furthermore, the ultimate tensile strength (250 MPa) and elongation (14.5%) of the alloy with a Zn/Al mass ratio of 3 were considerably increased compared to those of the as-ECAPed alloys with Zn/Al ratios of 2.5 and 3.5 (ultimate tensile strength and elongation of 215 MPa and 13% and 184 MPa and 10%, respectively). This significant enhancement was attributed to extensive grain boundary strengthening, precipitation strengthening, and higher work hardening capacity as well as texture randomization. The strength and ductility of the as-ECAPed alloys are also discussed in terms of the I-phase and Mg 2 Sn formation.

show abstract

Section: Introductionmentioning

confidence: 99%

Microstructures and mechanical properties of as-ECAPed Mg–8Sn alloys with the combined addition of Zn and Al

et al. 2017

View full text Add to dashboard Cite

show abstract

“…As expected for a material with low stacking fault energy[43] the presence of this high fraction of twin boundaries in the microstructure shows that formation of annealing twins is an important phenomenon during the recrystallization of this alloy. Twin domains are favorable nucleation sites for DRX due to their high stored deformation energy[44].…”

mentioning

confidence: 99%

Microstructural evolution and constitutive equations of Inconel 718 alloy under quasi-static and quasi-dynamic conditions

et al. 2016

View full text Add to dashboard Cite

The deformation behavior of IN718 superalloy was investigated using the hot compression tests in the temperature range of 950-1100 °C, and strain rates covering the quasi-static to the quasi-dynamic regions (0.001-10 s-1). The shape of flow curves as well as the corresponding work hardening rates analysis was utilized to reveal the dynamic recrystallization (DRX) phenomena. DRX was the dominant restoration mechanism in the whole temperature and strain rate domains, which was characterized by the optical and EBSD images. Extended flow softening was observed at high strain rates due to the adiabatic heating and dislocations interaction. In addition to the assessment the capability of Sellars equations, a new constitutive equation based on the multiple variable regression analysis was proposed for modeling the peak stress as a function of strain rate and temperature. Besides the simple form of the proposed model, it has a good accuracy for predicting the peak stress.The deformation behavior of IN718 superalloy was investigated using the hot compression tests in the temperature range of 950-1100 °C, and strain rates covering the quasi-static to the quasi-dynamic regions (0.001-10 s-1). The shape of flow curves as well as the corresponding work hardening rates analysis was utilized to reveal the dynamic recrystallization (DRX) phenomena. DRX was the dominant restoration mechanism in the whole temperature and strain rate domains, which was characterized by the optical and EBSD images. Extended flow softening was observed at high strain rates due to the adiabatic heating and dislocations interaction. In addition to the assessment the capability of Sellars equations, a new constitutive equation based on the multiple variable regression analysis was proposed for modeling the peak stress as a function of strain rate and temperature. Besides the simple form of the proposed model, it has a good accuracy for predicting the peak stress.Peer ReviewedPostprint (published version

show abstract

“…However, the slow-speed extruded alloys usually exhibit a bimodal microstructure containing large areas of coarse unDRXed grains elongated along the extrusion direction (ED), which deteriorates the room temperature ductility due to the twinning activity during tensile deformation [5][6][7]. To overcome this issue, extensive effort has been directed toward obtaining fine and homogeneous grain structure by promoting DRX, and thus enhanced strength and ductility, such as double extrusion [8,9], aging prior to extrusion [10,11] and cold forging prior to extrusion [12,13]. Park et al [12,13] reported that cold forging a homogenized billet at room temperature prior to extrusion can improve the tensile properties of extrudates by inducing numerous twins in the billet, which provided more nucleation sites for DRX during extrusion, leading to an increase in the DRX fraction of the extruded alloy.…”

Section: Introductionmentioning

confidence: 99%

“…To overcome this issue, extensive effort has been directed toward obtaining fine and homogeneous grain structure by promoting DRX, and thus enhanced strength and ductility, such as double extrusion [8,9], aging prior to extrusion [10,11] and cold forging prior to extrusion [12,13]. Park et al [12,13] reported that cold forging a homogenized billet at room temperature prior to extrusion can improve the tensile properties of extrudates by inducing numerous twins in the billet, which provided more nucleation sites for DRX during extrusion, leading to an increase in the DRX fraction of the extruded alloy. Despite the twin-aided DRX, however, fully DRXed microstructure was still difficult to be achieved due to the low extrusion temperature of 200 o C, consequently resulting in undesirable ductility (20%).…”

Section: Introductionmentioning

confidence: 99%

Enhancing strength and ductility of Mg-Zn-Gd alloy via slow-speed extrusion combined with pre-forging

Jiang

Nakata

et al. 2017

Journal of Alloys and Compounds

View full text Add to dashboard Cite

Mg-1.58Zn-0.52Gd (wt.%) alloy was subjected to slow-speed extrusion at 350 o C and 400 o C combined with hot pre-forging. The extruded alloy without pre-forging exhibited a bimodal microstructure, consisting of fine dynamically recrystallized (DRXed) grains and coarse unDRXed grains elongated along the extrusion direction, and strong basal texture, while pre-forging changed the bimodal structure into fully DRXed microstructure with finer grains and weaker extrusion texture. The fine and homogeneous extruded microstructure in the pre-forged alloy was mainly ascribed to the combined effect of refined starting microstructure just before extrusion, continuous DRX mechanism during extrusion and pinning effect induced by fine Mg3Zn3Gd2 precipitates. The pre-forged alloy exhibited superior balance of strength and ductility, as well as yield asymmetry, to the non-forged alloy after extrusion. The pre-forged alloy extruded at 350 o C and 400 o C showed highly improved elongation of 27.9% and 34.8%, respectively, mainly due to the formation of fully DRXed microstructure with fine grains through suppressing the activity of {10 1} contraction and {10 1}-{10 2} double twins during tensile deformation.

show abstract

Effect of cold pre-forging on the microstructure and mechanical properties of extruded Mg–8Sn–1Al–1Zn alloy

Cited by 35 publications

References 19 publications

Microstructures and mechanical properties of as-ECAPed Mg–8Sn alloys with the combined addition of Zn and Al

Microstructures and mechanical properties of as-ECAPed Mg–8Sn alloys with the combined addition of Zn and Al

Microstructural evolution and constitutive equations of Inconel 718 alloy under quasi-static and quasi-dynamic conditions

Enhancing strength and ductility of Mg-Zn-Gd alloy via slow-speed extrusion combined with pre-forging

Contact Info

Product

Resources

About