Processing, Microstructure and Mechanical Properties of SiCp/AZ91 Mg Matrix Composites Fabricated by Squeeze Casting

2007 ◽  
Vol 546-549 ◽  
pp. 499-502
Author(s):  
X. Qiu ◽  
Xiao Jun Wang ◽  
Ming Yi Zheng ◽  
Kun Wu

The fabrication processing, mechanical properties and fracture characters of SiCp/AZ91 magnesium matrix composites fabricated by squeeze casting were investigated. The SiC particles with different diameters (5μm, 20μm and 50μm) were employed as the reinforcement in the composites, the volume fraction of them was 50% in all cases. Experimental results showed that when the size of SiC particle decreased, the tensile properties of the composite increased. The tensile properties of SiCp/AZ91 composite with small particles are controlled by the properties of matrix alloy and the strength of the interface between the matrix and reinforcements, but the composites reinforced by large particles are controlled by the fracture of the particles.

2010 ◽  
Vol 152-153 ◽  
pp. 11-18 ◽  
Author(s):  
Song Jeng Huang ◽  
Yo Zhi Dai ◽  
Yeau Ren Jeng

This paper investigated the volume fraction effect of micro-sized SiC on the tribological behavior of SiCp reinforced AZ91D Mg-based metal-matrix composites (MMCs). The Mg MMCs were prepared by the melt-stirring technique for wear tests. The hardness and coefficient of friction of Mg MMCs increase as increasing volume fraction of SiC particle in MMCs. The SiCp/AZ91D MMCs exhibit superior wear resistance under lower and moderate sliding condition. However, the effects of the SiC particle reinforcements on wear resistance are not as conclusive under severe sliding condition (50N-1500 rpm for all vol.% of MMCs, 50N-1000rpm for 3 vol. % MMCs), since the matrix of MMCs were softened at elevated temperature under such severe condition. However, the incorporation of SiC particles could enhance the wear resistance of AZ91D matrix alloy for most of the sliding conditions.


2011 ◽  
Vol 694 ◽  
pp. 635-639 ◽  
Author(s):  
Wei Xue Li ◽  
Yun Feng Nie ◽  
Dun Dong Wang

AZ91D alloy composites reinforced by CNTs/SiCp were fabricated using stir casting process. The mechanical properties of the composites were tested, observed and analyzed the microstructure, the fractographs were observed and analyzed via scanning electron microscope. The results showed that CNTs/SiCp could not only refine the grains of the composites, but also bear the load of resistance to deformation. Compared with the matrix alloy, the tensile strength, the elastic modulus, the micro-hardness and the elongation rate of the composites had been enhanced significantly. But the mechanical properties would be fell down with the more addition of CNTs/SiCp.


2016 ◽  
Vol 256 ◽  
pp. 181-185
Author(s):  
Zhao Hui Wang ◽  
Bo Li ◽  
Xian Du ◽  
Ke Liu ◽  
Shu Bo Li ◽  
...  

In this paper, In Situ AlN particles reinforced magnesium matrix composites were fabricated. The results show that the AlN phases can be In Situ synthesized in AZ91D alloy with the addition of Mg3N2. The microstructure and phases of the matrix alloys and the composites were investigated by OM, SEM and XRD. The hardness and mechanical properties of the matrix alloys and the composites were also obtained. Compared with those of the matrix alloy, the grains of composites were refined obviously and the mechanical properties of composites were improved significantly. The microstructural analysis indicates that the AlN particles can act as the heterogeneous nucleation of α-Mg phases in the composites. The strengthening mechanism of the composites with AlN particles was discussed.


Author(s):  
G. Pitchayyapillai ◽  
M. Jinnah Sheik Mohamed ◽  
G. Dhanraj ◽  
R. Malkiya Rasalin Prince ◽  
M. Rajeshwaran ◽  
...  

Author(s):  
K H W Seah ◽  
S C Sharma ◽  
M Krishna

The mechanical properties and the fracture mechanism of composites consisting of ZA-27 alloy reinforced with titanium dioxide particles were investigated with the primary objective of understanding the influence of the particulate reinforcement on the mechanical behaviour of the ZA-27 alloy. The titanium dioxide particle content in the composites ranged from 0 to 6 per cent, in steps of 2 wt %. The composites were fabricated by the stir casting technique in which the reinforcement particles were dispersed in the vortex created in the molten matrix alloy. The study revealed improvements in Young's modulus, ultimate tensile strength (UTS), compressive strength, yield strength and hardness of the composites as the titanium dioxide content was increased, but at the expense of ductility and impact strength. The fracture behaviour of the composite was also significantly influenced by the presence of titanium dioxide particles. Eventual fracture was a result of crack propagation through the matrix as well as through the reinforcing particles. Scanning electron microscopy and fractography analyses were carried out to provide suitable explanations for the observed phenomena.


Author(s):  
M. A. Salem ◽  
I. G. El-Batanony ◽  
M. Ghanem ◽  
Mohamed Ibrahim Abd ElAal

Different Al-SiC metal matrix composites (MMCs) with a different matrix, reinforcement sizes, and volume fractions were fabricated using ball milling (BM) and powder metallurgy (PM) techniques. Al and Al-SiC composites with different volume fractions were milled for 120 h. Then, the Al and Al-SiC composites were pressed under 125 MPa and finally sintered at 450 °C. Moreover, microsize and combination between micro and nano sizes Al-SiC samples were prepared by the same way. The effect of the Al matrix, SiC reinforcement sizes and the SiC volume fraction on the microstructure evolution, physical and mechanical properties of the produced composites was investigated. The BM and powder metallurgy techniques followed by sintering produce fully dense Al-SiC composite samples with different matrix and reinforcement sizes. The SiC particle size was observed to have a higher effect on the thermal conductivity, electrical resistivity, and microhardness of the produced composites than that of the SiC volume fraction. The decreasing of the Al and SiC particle sizes and increasing of the SiC volume fraction deteriorate the physical properties. On the other hand, the microhardness was enhanced with the decreasing of the Al, SiC particle sizes and the increasing of the SiC volume fraction.


2015 ◽  
Author(s):  
Risa Yoshizaki ◽  
Kim Tae Sung ◽  
Atsushi Hosoi ◽  
Hiroyuki Kawada

Carbon nanotubes (CNTs) have very high specific strength and stiffness. The excellent properties make it possible to enhance the mechanical properties of polymer matrix composites. However, it is difficult to use CNTs as the reinforcement of long fibers because of the limitation of CNT growth. In recent years, a method to spin yarns from CNT forests has developed. We have succeeded in manufacturing the unidirectional composites reinforced with the densified untwisted CNT yarns. The untwisted CNT yarns have been manufactured by drawing CNTs through a die from vertically aligned CNT arrays. In this study, the densified untwisted CNT yarns with a polymer treatment were fabricated. The tensile strength and the elastic modulus of the yarns were improved significantly by the treatment, and they were 1.9 GPa and 140 GPa, respectively. Moreover, the polymer treatment prevented the CNT yarns from swelling due to impregnation of the matrix resin. Finally, the high strength CNT yarn composites which have higher volume fraction than a conventional method were successfully fabricated.


2011 ◽  
Vol 415-417 ◽  
pp. 2244-2247 ◽  
Author(s):  
Feng Yan ◽  
Rong Xin Guo ◽  
Hai Ting Xia ◽  
Hai Yu ◽  
Yu Bo Zhang

The copper matrix composites reinforced by different WCP volume fraction were fabricated via Vacuum Hot-pressed Sintering technique. The tensile performance and fracture behavior of WCP/Cu composites were studied by uniaxial tension tests and the fracture surfaces were examined by SEM. The test results of mechanical properties show that the WCP/Cu composites exhibit obvious improvement of tensile property comparing with that of the matrix. The fracture surface morphology indicate a trend that the fracture of WCP/Cu composites changes from debonding to cleavage with the increase of the WCP volume fraction.


1996 ◽  
Vol 459 ◽  
Author(s):  
J. H. Lee ◽  
K. Hamada ◽  
K. Miziuuchia ◽  
M. Taya ◽  
K. Inoue

ABSTRACT6061 Al-matrix composite with TiNi shape memory fiber as reinforcement has been fabricated by vacuum hot pressing to investigate the microstructure and mechanical properties. The yield stress of this composite increases with increasing amount of prestrain, and it also depends on the volume fraction of fiber and heat treatment. The smartness of the composite is given due to the shape memory effect of the TiNi fiber which generates compressive residual stresses in the matrix material when heated after being prestrained. Microstructual observations have revealed that interfacial reactions occur between the matrix and fiber, creating two intermetallic layers. The flow strength of the composite at elevated temperatures is significantly higher than that of the matrix alloy without TiNi fiber.


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