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Chen Q.,Xi'an Technological University | Yang Z.,Xi'an Technological University | Li J.,Xi'an Technological University | Wu Y.,PLA Representative Office in Factory No.616 | And 2 more authors.
Cailiao Yanjiu Xuebao/Chinese Journal of Materials Research | Year: 2013

The microstructure and mechanical properties in different extrusion directions of Mg-9.8Gd-1.6Y-0.02Zn-0.5Zr(GW102 alloy) bar were investigated by optical microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM). The results show that the microstructure of GW102 alloy mainly consist of supersaturated solid solution, a few particle Mg5(Y0.6Gd0.4) phase and nonequilibrium phases Mg3(Gd0.5, Y0.5). The β″ and β′ phases formed after aging treatment at 200°C for 60 h. The anisotropy is obvious in this magnesium alloy. The tensile strength and elongation in vertical direction of extrusion state after aging treatment was significantly lower than that in extrusion direction at room temperature. The interaction of LPSO and dislocations and the precipitates-free zone(PFZ) appeared in the grain boundary were investigated, whose influence on mechanical properties of GW102 alloy was discussed. © Copyright.

Yang Z.,Xi'an Technological University | Li J.-P.,Xi'an Technological University | Wu Y.-X.,PLA Representative office in Factory No. 616 | Liu J.-L.,Foundry of North General Power Group Co. | Yang Z.-L.,Foundry of North General Power Group Co.
Zhuzao/Foundry | Year: 2013

The effect of Gd and Y content on microsturcture and tensile properties of Mg-Gd-Y-0.5Zr Alloy by OM, SEM and XRD was studied. The results show that the tensile strength of GWxy alloys increases gradually and the elongation reduces gradually with Gd content increasing. With Y content increasing, however, the tensile strength and elongation of GWxy alloys increase first, then reduces. When Gd content is 9%, Y content is 3% (i.e. GW93 alloy), the comprehensive properties is the best in the GWxy alloys. The tensile strength of GW93 alloy at as-cast state is 330-350 MPa and elongation is 6%. Moreover, because there is replacement between Gd and Y, α(Mg) solid solution, divorced eutectic compound Mg5(Y, Gd), particle Mg5(Gd, Y) or Mg24 (Y, Gd)5, non-equilibrium crystallization phase Mg3(Gd,Y) or Mg2(Y, Gd) will simultaneously exist in Mg-Gd-Y-0.5Zr alloy at room temperature.

Gao P.H.,Xi'an Technological University | Li J.P.,Xi'an Technological University | Yang Z.,Xi'an Technological University | Guo Y.C.,Xi'an Technological University | And 4 more authors.
Applied Mechanics and Materials | Year: 2013

In this paper, MCrAlY bonding layer was prepared through high velocity-oxygen fuel spray on the AZ91 magnesium alloy surface. 8wt%YSZ ceramic layer was deposited on the surface of bonding layer through atmospheric plasma spraying. The coatings were characterized by XRD and SEM. The hardness of the coating was tested. The coefficients of thermal expansion of the coating were measured through TMA. It was found that there were un-melted 8YSZ particles surrounded by melted particles layer by layer. Parts of ZrO2 transited from cubic to tetragonal. The microhardness of the YSZ coating and bonding layer were 832.1Hvo.3 and 700.3Hvo.3, respectively. The coefficients of thermal expansion of the magnesium alloy, MCrAlY layer and YSZ coating were 42.46 x 10-6 k-1, 15.26 x 10-6 k-1, 9.28x 10-6 k-1, respectively. The bonding coat matched the magnesium alloy substrate and the YSZ coating well. The dimension of AZ91 magnesium alloy sample was very stabilized before and after coating deposition. © (2013) Trans Tech Publications, Switzerland.

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