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Quan-an Li

Bio: Quan-an Li is an academic researcher from Henan University of Science and Technology. The author has contributed to research in topics: Ultimate tensile strength & Deformation (engineering). The author has an hindex of 2, co-authored 3 publications receiving 19 citations.

Papers
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TL;DR: In this paper, the microstructure evolution and deformation behavior of Mg-5Gd-3Y-(1Sn)-0.5Zr alloys were studied by transmission electron microscopy and electron backscattering technology.
Abstract: We have studied the microstructure evolution and deformation behavior of Mg-5Gd-3Y-(1Sn)-0.5Zr alloys during hot compression (T = 350 °C, 400 °C, 450 °C and 500 °C, e ˙ = 0.002 s−1, 0.01 s−1, 0.1 s−1 and 1 s−1) by transmission electron microscopy and electron backscattering technology. Sn can promote dynamic precipitation to activate the particle-stimulated nucleation (PSN) mechanism induced by the cluster precipitates and promote and dynamic recrystallization (DRX); in addition, Sn can inhibit the formation of high-angle grain boundaries (HAGBs) by reducing the activation of pyramidal and slip and delaying DRX. The two processes are in a competitive relationship with each other in the hot deformation of Mg-Gd-Y-Sn-Zr alloys. At low temperatures (350 °C–400 °C) and high strain rates, the former dominates: DRX is promoted, accompanied by a decrease in flow stress. At high temperatures (450 °C–500 °C) and low strain rates, the latter is dominant due to the absence of dynamic precipitation: DRX is delayed, and flow stress is increased accordingly. Flow stress between the two extreme deformation conditions is determined by the competitive relationship between them. We also found that the addition of Sn could increase the thermal deformation activation energy of Mg-Gd-Y-Zr alloys, weaken the texture and inhibit twin growth. Finally, we constructed a schematic diagram of the DRX mechanism during the thermal deformation process to illustrate the effects of PSN, CDRX, and DDRX on the evolution of the microstructure in detail.

28 citations

Journal ArticleDOI
TL;DR: In this article, the microstructure of alloy was investigated after solution and aging treatment (i.e., T6 heat treatment), and the results showed that the aged alloy was mainly composed of α-Mg matrix and dispersed long-period ordered β′ precipitates.
Abstract: The Mg–12Gd–2Y–0.5Sm–0.5Sb–0.5Zr (wt.%) alloy was prepared by casting technology. The microstructure of alloy was then investigated after solution and aging treatment (i.e., T6 heat treatment). Tensile tests were performed at a crosshead speed of 1 mm/min at ambient and elevated temperature atmosphere. The results show that the aged alloy was mainly composed of α-Mg matrix and dispersed long-period ordered β′ precipitates. At 250 °C, the alloy has shown the superior tensile strength (i.e., 345.5 MPa). The remarkable high strength of experimental alloy was mainly associated with solution strengthen of RE and precipitation strengthening of dispersive LPO structure β′ precipitates in Mg matrix. The LPO β′ precipitates provide important strengthening sources in experimental alloy, especially at elevated temperatures.

19 citations

Journal ArticleDOI
TL;DR: In this paper, a CeO 2 -modified aluminide coating was obtained by composite electrodeposition Ni and CeO2 particles on 20 steel with different holding time using pack cementation and the growth kinetics curve was given with computer fitting by measuring the thickness of the layer.
Abstract: A CeO 2 - modified aluminide coating was obtained by composite electro-deposition Ni and CeO 2 particles on 20 steel with different holding time using pack cementation. The growth kinetics curve was given with computer fitting by measuring the thickness of the layer. Scanning electronic microscopy and X-ray energy dispersive spectrometry were used to analyze the microstructure and components of the layer. The results showed that the content of CeO 2 was up to 5.21 wt.% in the rich area of NiAl coatings, which restrain the interdiffusion between the coating and the base during the oxidation process at high temperature. Meanwhile, the growth curve obtained could offer an important basis to forecasting and controlling the depth of the coating.

3 citations


Cited by
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TL;DR: In this article, the compositional dependence of the age hardening response and high temperature tensile properties of the Mg- x Gd-3Y-0.5Zr alloys are investigated.
Abstract: In this study, the compositional dependence of the age hardening response and high temperature tensile properties of the Mg– x Gd–3Y–0.5Zr ( x =3, 6, 10, and 12 wt%) alloys are investigated. The amount of cuboid-shaped phases and β ′ precipitates increased significantly with increasing the Gd content. The Mg–10Gd–3Y–0.5Zr alloy exhibited the maximum ultimate tensile strength at room temperature, while at higher temperatures the Mg–12Gd–3Y–0.5Zr alloy exhibited the maximum yield strength and ultimate tensile strength. The yield strength and ultimate tensile strength of the Mg–12Gd–3Y–0.5Zr alloy increased with the test temperature and showed its maximum at 150 °C, and then decreased as the temperature increased further. The Mg–12Gd–3Y–0.5Zr alloy maintained a high ultimate tensile strength of more than 300 MPa up to 250 °C. The superior high temperature tensile strength of the tested alloy is mainly associated with solution strengthening and precipitation hardening of the cuboid-shaped phases and β ′ precipitates in Mg matrix. Especially, β ′ precipitates can hinder the dislocation movement at high temperature.

84 citations

Journal ArticleDOI
TL;DR: In this article, the agehardening behavior and mechanical properties of the extruded Mg-2Gd-1.2Y-0.5 Zn (at.%) alloy with Zr or Mn additions were investigated.

67 citations

Journal ArticleDOI
TL;DR: In this paper, the microstructure and mechanical properties of the extruded Mg95.5Y3Zn1.5 alloy under different heat treatment were systematically investigated by optical microscopy (OM), scanning electron microscopy, transmission electron microscope (TEM) and an electronic universal testing machine.
Abstract: The microstructure and mechanical properties of the extruded Mg95.5Y3Zn1.5 alloy under different heat treatment were systematically investigated by optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and an electronic universal testing machine. The results show that the as-extruded alloy is composed of 18R LPSO stripes and α-Mg matrix with stacking faults (SFs) in it. The fine 14H LPSO lamellas are formed in α-Mg matrix near the areas of SFs during solution treatment at 500 °C for 8 h. A great number of fine β′ phases are precipitated in the α-Mg matrix of T6-treated (aging of the T4-treated alloy at 225 °C for 24 h) and T5-treated (aging of the as-extruded alloy at 225 °C for 32 h) alloys. Moreover, the SFs which were first observed in extruded alloy are retained in T5-staged specimen, and exhibit a cross arrangement with β′ precipitates. The absence of 14H LPSO phase in T5-treated alloy indicates that the 14H structure cannot be formed during aging at 225 °C. Tensile tests reveal that the presence of 14H lamellas improves the ductility of the alloy, but decreases the strength, suggesting that the 18R LPSO stripes are more effective in strengthening the alloy than 14H LPSO lamellas. The T6-staged alloy exhibits superior comprehensive mechanical properties with ultimate tensile strength of 358 MPa, tensile yield strength of 226 MPa and elongation of 6.1% at room temperature.

49 citations

Journal ArticleDOI
TL;DR: In this paper, the effects of Gd and Y solutes on aging behavior and corresponding mechanical properties of the extruded Mg-Gd-Zn-Mn alloys at room and elevated temperatures were investigated.
Abstract: This paper investigated the effects of Gd and Y solutes on aging behaviour and corresponding mechanical properties of the extruded Mg–Gd(-Y)-Zn-Mn alloys at room and elevated temperatures. The results show that aging treatment provided significant improvement of ~100 MPa in strength by forming ellipsoidal β ′ nanophases in the as-extruded alloys. Partially substituting Y for Gd in the as-extruded Mg-Gd-Zn-Mn alloys can delay age-hardening response, but improve the strength increment after aging treatment. As the Y/Gd atomic ratio changed from 0 to 1, the Mg-1.75Gd-0.75Y-0.5Zn–Mn(at.%) alloy with a Y/Gd atomic ratio of 0.4 obtained the higher peak-hardness and mechanical properties. Enhanced age-hardening response and better mechanical properties were detected after separate additions of Y and Gd. The extruded-T5 Mg-2.5Gd-0.75Y-0.5Zn-0.3Mn alloy exhibited superior ultimate tensile strengths of 520 MPa at room temperature, 344 MPa at 250 °C, and 225 MPa at 300 °C. Fracture behaviours reveal that a change in predominant deformation mechanism from one based on dislocations to one mediated by grain boundary (GB) processes was found as the tensile temperatures arise from 250 °C to 300 °C. The activation of GB sliding of the fine grains partially resulted in the decrease of tensile strength at 300 °C.

47 citations

Journal ArticleDOI
TL;DR: In this paper, the effects of Sm on the microstructure and mechanical properties of Mg-11Gd-2Y-0.6Al alloy were investigated by X-ray diffraction, optical microscopy, scanning electron microscopy and energy dispersive spectrometry.

30 citations