Microstructure and mechanical properties of Mg 97 Zn 1 Y 2 alloy reinforced with LPSO structure produced by semisolid squeeze casting

2018 ◽  
Vol 732 ◽  
pp. 359-367 ◽  
Author(s):  
Shulin Lü ◽  
Shusen Wu ◽  
Xiong Yang ◽  
Liangyan Hao ◽  
Wei Guo ◽  
...  
2016 ◽  
Vol 879 ◽  
pp. 530-535
Author(s):  
Xiao Gang Fang ◽  
Shu Sen Wu ◽  
Shu Lin Lü

Mg-Zn-Y alloys containing a thermally stable icosahedral quasicrystal phase (I-phase) will have wide application future on condition that primary α-Mg dendrite and the I-phase can be refined during the casting process. In this research, the microstructure and mechanical properties of the rheo-squeeze casting (RSC) Mg-6Zn-1.4Y alloys have been investigated. The Mg alloy melt was exposed to ultrasonic vibration (USV) with different acoustic power densities from 0 W/mL to 9 W/mL, and then the slurry was formed by squeeze casting. The results show that good semi-solid slurry with fine and spherical α-Mg particles could be obtained with the acoustic power density of 6 W/mL, and the average grain size and shape factor of primary α-Mg were 32 μm and 0.76, respectively. Meanwhile the coarse eutectic I-phase (Mg3Zn6Y) was refined obviously and dispersed uniformly. Compared with the samples without USV, the tensile strength and elongation of the RSC casting samples with 6 W/mL acoustic power density were elevated by 10.6% and 55.5%, respectively.


2016 ◽  
Vol 850 ◽  
pp. 511-518 ◽  
Author(s):  
Hai Jun Liu ◽  
Lie Jun Li ◽  
Jian Wei Niu ◽  
Ji Xiang Gao ◽  
Chuan Dong Ren

The effects of Mg and Cu additions with different contents on the mechanical properties of Al-Si alloy prepared by indirect squeeze casting have been experimentally investigated. The microstructure and mechanical properties of as-cast and T6-treated Al-Si-Cu-Mg alloys were tested by OM, SEM, DSC and tensile measurement, where the samples were produced by artificial aging at 180°C for 8 h after solution treatment at 540°C for 4 h. It has been found that for the as-cast alloys, with increasing contents of Mg and Cu the tensile strength (UTS) and yield strength (YS) increased, while the percentage elongation (El) decreased. And the optimal mechanical properties of Al-Si-Cu-Mg alloys were obtained under the content ratio of Cu/Mg within 4, where the UTS and El reached 426 MPa and 6.3% after T6 treated, respectively.


2020 ◽  
Vol 67 (1) ◽  
pp. 101-105
Author(s):  
Yongxin Zhou ◽  
Qian Li ◽  
Zhiguo Xing ◽  
Renze Zhou ◽  
Zhenhua Huang ◽  
...  

Purpose This paper aims to investigate the effect of aluminum addition on the microstructure and mechanical properties of Mg-8Gd-4Y-1Zn alloy. Design/methodology/approach Mg-8Gd-4Y-1Zn-xAl (x = 0, 0.5, 1.0, 1.5, 2.0 Wt.%) alloys were prepared by the conventional gravity casting technology, and then microstructures, phase composition and mechanical properties were investigated by material characterization method, systematically. Findings Results show that the as-cast microstructure of Mg-8Gd-4Y-1Zn alloy mainly consists of a-Mg matrix as well as Mg12REZn (18 R LPSO structure), and island-like Mg3(RE, Zn) phase is distributed at the grain boundary. The addition of a small amount of Al (0.5 Wt.%) can decrease the content of island-like Mg3(RE, Zn) phase, but significantly increase the content of long-period stacking ordered (LPSO) structure, resulting in the improvement of both tensile strength and elongation of Mg-8Gd-4Y-1Zn alloy. However, the addition of excessive Al will consume Re element and decrease the amount of LPSO structure, leading to the decrease of tensile properties. When the content of Al is 0.5 Wt.%, the tensile strength and elongation are 225 MPa and 9.0% of Mg-8Gd-4Y-1Zn alloy, which are 14% and 29% higher than that of Mg-8Gd-4Y-1Zn alloy, respectively. Originality/value Adding aluminum to Mg-8Gd-4Y-1Zn alloy strengthens its mechanical properties. And the effect of Al content on the alloy strengthening. The formation mechanism of LPSO structure with different aluminum content was revealed.


2018 ◽  
Vol 941 ◽  
pp. 1607-1612 ◽  
Author(s):  
Shu Lin Lü ◽  
Xiong Yang ◽  
Liang Yan Hao ◽  
Shu Sen Wu

In this work, ultrasonic rheocasting was used to refine the microstructures of Mg alloys reinforced with long period stacking ordered (LPSO) phase. The semisolid slurries of Mg-Zn-Y and Mg-Ni-Y alloys were prepared by ultrasonic vibration (UV) and then formed by rheo-squeeze casting under high squeeze pressure (~ 400 MPa). The effects of UV and squeeze pressure on microstructure and mechanical properties of the Mg alloys were studied. The results reveal that UV and rheo-squeeze casting can significantly refine the LPSO structure and alpha-Mg matrix in Mg alloys, but they cannot change the phase compositions of the alloys or the type of LPSO phase. When the squeeze pressure is 400 MPa, the average thickness of LPSO phase is decreased, and the block LPSO structure is completed eliminated and uniformly distributed at the grain boundaries. Compared with the gravity cast alloys without UV, mechanical properties of the rheocast Mg alloys were enhanced and reached the maximums when the squeeze pressure was 400 MPa.


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