Primary Mg2Si phase and Mg2Si/α-Mg interface modified by Sn and Sb elements in a Mg-5Sn-2Si-1.5Al-1Zn-0.8Sb alloy

In this paper, the microstructure and mechanical properties of two magnesium matrix composites—a hypoeutectic with 1.9 wt% Mg2Si phase and a hypereutectic with 19 wt% Mg2Si compound—were analyzed. The investigated materials were prepared using the gravity casting method. Microstructure analyses of the fabricated composites were carried out by XRD and light microscopy. The tensile and compression strength as well as yield strength of the composites were examined in both uniaxial tensile and compression tests. The microstructure of the hypoeutectic composite was in agreement with the phase diagram and composed of primary Mg dendrites and an Mg–Mg2Si eutectic mixture. For the hypereutectic composite, besides the primary Mg2Si phase and eutectic mixture, additional magnesium dendrites surrounding the Mg2Si compound were observed due to nonequilibrium solidification conditions. The composites exhibited a rise in the examined mechanical properties with an increase in the Mg2Si weight fraction and also a higher tensile and compression strength in comparison to the pure magnesium matrix (cast in the same conditions). Additionally, analyses of fracture surfaces of the composites carried out using scanning electron microscopy (SEM + EDX) are presented.

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Synthesis of octahedron and truncated octahedron primary Mg2Si by controlling the Sb contents

CrystEngComm ◽

10.1039/c2ce26649k ◽

2013 ◽

Vol 15 (9) ◽

pp. 1787 ◽

Cited By ~ 32

Author(s):

Lei Chen ◽

Hui-Yuan Wang ◽

Dan Luo ◽

Hua-Yuan Zhang ◽

Bo Liu ◽

...

Keyword(s):

Truncated Octahedron ◽

Primary Mg2si

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Effect of Si, Sr Additions on Microstructure and Mechanical Properties of AZ91 Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.546-549.179 ◽

2007 ◽

Vol 546-549 ◽

pp. 179-182

Author(s):

S.B. Li ◽

Zhi Wen Zou ◽

Shou Mei Xiong

Keyword(s):

Mechanical Properties ◽

Silicon Content ◽

Room Temperature ◽

Chinese Script ◽

Az91 Alloy ◽

Permanent Mold ◽

Remarkable Effect ◽

Mg2si Phase ◽

Β Phase ◽

Si Content

In present work, Si and Sr elements were added into AZ91 alloy and cast directly into test samples using permanent mold. Mechanical properties of the samples at room temperature were evaluated by tensile test and the microstructure was analyzed. The results show that β-phase (Mg17Al12) of AZ91 alloy decreases with the addition of Si element and Mg2Si phase forms at the same time. Irregular Mg2Si phase precipitates preferentially at the grain boundaries at a low silicon content level. With the increase of the Si content, Mg2Si phase shows a complicated “Chinese- script” shape distributed at the grain boundary which leads to a lower ultimate tensile strength. Subsequently, the addition of Sr element has a remarkable effect on the form and distribution of Mg2Si phase of AZ91-Si alloys.

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Effect of KBF4 Addition on the Microstructure of Mg-6Zn-1Si Alloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.535-537.996 ◽

2012 ◽

Vol 535-537 ◽

pp. 996-999 ◽

Cited By ~ 4

Author(s):

Bao Feng Zhang ◽

Qi Chen ◽

Xiao Wei Chen ◽

Hong Liang Zhao

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Optical Microscopy ◽

Energy Dispersive Spectrometer ◽

Energy Dispersive ◽

Chinese Script ◽

Mg2si Phase ◽

Small Block ◽

Average Size ◽

Scanning Electron

In this study, the effect of KBF4 addition on the microstructure of the Mg-6Zn-1Si alloy has been investigated by Optical Microscopy (OM), Scanning Electron Microscopy (SEM) with Energy Dispersive Spectrometer(EDS). At 1.5wt% KBF4 addition, the morphology of Mg2Si phase completely changed from Chinese script type into uniformly, dispersedly distributed graininess or small block, with the average size of the Mg-6Zn-1Si alloy decreasing from 135μm to 82μm.

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