Microstructure and Properties of In-Situ Synthesized (Al3Zr+Al2O3)p/A356 Composites

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1292-1296 ◽  
Author(s):  
Y. T. Zhao ◽  
Q. X. Dai ◽  
X. N. Cheng ◽  
S. C. Sun

A novel in-situ reaction system Al-Zr-O was developed. In-situ Al3Zr and Al 2 O 3 particulate reinforced A356 alloy matrix composites have been fabricated by direct melt reaction method. The results show that the maximum size of Al3Zr and Al 2 O 3 particulate synthesized in the system ZrOCl2-A356 is 1um and 3um respectively, and they are well distributed in the matrix. The investigation shows that Al3Zr crystal is in the shape of polyhedron and rectangle. There is a faceted growth phenomenon on Al3Zr crystal surface. It is firstly found that the Al3Zr crystal grows in the mechanism of twin. The twin plane is [Formula: see text], and the twinning direction is [Formula: see text]. The crystal morphology of in-situ[Formula: see text] particulate is rectangle or sphere. Furthermore. ( Al 3 Zr+Al 2 O 3) p / A356 composites have not only higher tensile strength at room temperature (376.2MPa) but also higher yield strength (319.4MPa) and higher tensile strength at elevated temperature (200°C) than that of A356 alloy.

2005 ◽  
Vol 475-479 ◽  
pp. 317-320 ◽  
Author(s):  
Jing Pei Xie ◽  
Ji Wen Li ◽  
Zhong Xia Liu ◽  
Ai Qin Wang ◽  
Yong Gang Weng ◽  
...  

The in-situ Ti alloying of aluminium alloys was fulfilled by electrolysis, and the material was made into A356 alloy and used in automobile wheels. The results show that the grains of the A356 alloy was refined and the second dendrites arm was shortened due to the in-situ Ti alloying. Trough 3-hour solution treatment and 2-hour aging treatment for the A356 alloy, the microstructures were homogeneous, and Si particles were spheroid and distribute in the matrix fully. The outstanding mechanical properties with tensile strength (σb≥300Mpa) and elongation values (δ≥10%) have been obtained because the heat treatment was optimized. Compared with the traditional materials, tensile strength and elongation were increased by 7.6~14.1% and 7.4~44.3% respectively. The qualities of the automobile wheels were improved remarkably.


Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3358 ◽  
Author(s):  
Hang Chen ◽  
Guangbao Mi ◽  
Peijie Li ◽  
Xu Huang ◽  
Chunxiao Cao

In this study, graphene-oxide (GO)-reinforced Ti–Al–Sn–Zr–Mo–Nb–Si high-temperature titanium-alloy-matrix composites were fabricated by powder metallurgy. The mixed powders with well-dispersed GO sheets were obtained by temperature-controlled solution mixing, in which GO sheets adsorb on the surface of titanium alloy particles. Vacuum deoxygenating was applied to remove the oxygen-containing groups in GO, in order to reduce the introduction of oxygen. The compact composites with refined equiaxed and lamellar α phase structures were prepared by hot isostatic pressing (HIP). The results show that in-situ TiC layers form on the surface of GO and GO promotes the precipitation of hexagonal (TiZr)6Si3 particles. The composites exhibit significant improvement in strength and microhardness. The room-temperature tensile strength, yield strength and microhardness of the composite added with 0.3 wt% GO are 9%, 15% and 27% higher than the matrix titanium alloy without GO, respectively, and the tensile strength and yield strength at 600 °C are 3% and 21% higher than the matrix alloy. The quantitative analysis indicates that the main strengthening mechanisms are load transfer strengthening, grain refinement and (TiZr)6Si3 second phase strengthening, which accounted for 48%, 30% and 16% of the improvement of room-temperature yield strength, respectively.


2011 ◽  
Vol 335-336 ◽  
pp. 137-141 ◽  
Author(s):  
Yuong Chen ◽  
Chang Jiang Zhang ◽  
Fan Tao Kong ◽  
Hong Zhi Niu ◽  
Fang Wu ◽  
...  

In the present study, Ti-6Al-2.5Sn-4Zr-0.7Mo-0.3Si-0.3Y alloy matrix composites reinforced with TiB and TiC were fabricated by combustion-assisted cast utilizing the reaction between titanium and B4C, graphite. The microstructure, room temperature mechanical properties were presented and discussed. Microstructural analysis of the composites revealed that the prior β grain size as well as the thickness of α colony significantly refined with increasing of volume fraction. At room temperature (RT), tensile strength and elastic modulus increase significantly, while the ductility drops gradually possibly because of the cracking of TiB whiskers and TiC particles.


2021 ◽  
pp. 002199832110055
Author(s):  
Zeeshan Ahmad ◽  
Sabah Khan

Alumnium alloy LM 25 based composites reinforced with boron carbide at different weight fractions of 4%, 8%, and 12% were fabricated by stir casting technique. The microstructures and morphology of the fabricated composites were studied by scanning electron microscopy and energy dispersive spectroscopy. Elemental mapping of all fabricated composites were done to demonstrate the elements present in the matrix and fabricated composites. The results of microstructural analyses reveal homogenous dispersion of reinforcement particles in the matrix with some little amount of clustering found in composites reinforced with 12% wt. of boron carbide. The mechanical characterization is done for both alloy LM 25 and all fabricated composites based on hardness and tensile strength. The hardness increased from 13.6% to 21.31% and tensile strength 6.4% to 22.8% as reinforcement percentage of boron carbide particles increased from 0% to 12% wt. A fractured surface mapping was also done for all composites.


2016 ◽  
Vol 25 (5-6) ◽  
pp. 165-169
Author(s):  
C. Rajaravi ◽  
P.R. Lakshminarayanan

AbstractThe paper describes a different condition of pouring temperature by sand and permanent mould to produce A356-6 wt% TiB2 metal matrix composites by in-situ method salt metal reaction route. The observation of SEM micrographs shows particle distribution of the TiB2 and it appears in hexagonal shape in Al matrix. The results of X-ray diffraction (XRD) analysis confirmed the formation of those TiB2 particulates and the results showed TiB2 particles are homogeneously dispersed throughout the matrix metal. Subsequent structure-property evaluation studies indicated sub-micron size reinforcement of in-situ formed TiB2 particles with improved physical and mechanical properties as compared to sand and permanent mould of Al-TiB2 composites. From, the permanent mould Al-TiB2 composite has an advantage of increase the properties over sand mould Al-TiB2 composite.


2015 ◽  
Vol 787 ◽  
pp. 583-587 ◽  
Author(s):  
V. Mohanavel ◽  
K. Rajan ◽  
K.R. Senthil Kumar

In the present study, an aluminum alloy AA6351 was reinforced with different percentages (1, 3 and 5 wt %) of TiB2 particles and they were successfully fabricated by in situ reaction of halide salts, potassium hexafluoro-titanate and potassium tetrafluoro-borate, with aluminium melt. Tensile strength, yield strength and hardness of the composite were investigated. In situ reaction between the inorganic salts K2TiF6 and KBF4 to molten aluminum leads to the formation of TiB2 particles. The prepared aluminum matrix composites were characterized using X-ray diffraction and scanning electron microscope. Scanning electron micrographs revealed a uniform dispersal of TiB2 particles in the aluminum matrix. The results obtained indicate that the hardness and tensile strength were increased with an increase in weight percentages of TiB2 contents.


1999 ◽  
Vol 14 (1) ◽  
pp. 68-74 ◽  
Author(s):  
Jian Zhang ◽  
Yu-qing Wang ◽  
Bing Yang ◽  
Ben-lian Zhou

Al/Mg2Si composites were in situ fabricated by the usual die-casting technique, and effects of the Si contents in the composites on microstructures and tensile strengths were investigated. Experimental results show that extra Si contents in Al/Mg2Si composites induce a ductile matrix and a uniform distribution of in situ particles. The refined microstructures lead to an obvious increase in both strength and ductility of the metal matrix composites (MMCs). The effects of extra Si on both the solidification process and fracture characteristics of the Al/Mg2Si composites were analyzed.


Tribologia ◽  
2019 ◽  
Vol 285 (3) ◽  
pp. 79-87 ◽  
Author(s):  
Jerzy MYALSKI ◽  
Andrzej Posmyk ◽  
Bartosz HEKNER ◽  
Marcin GODZIERZ

Carbon with an amorphous structure was used as a component to modify the tribological properties of engineering plastics. Its construction allows the formation of carbon-based wear products during friction, adhesively bonded to the surface of cooperating machine parts, acting as a solid lubricant. The work compares the tribological properties of two groups of composites with an aluminium alloy matrix in which glassy carbon appeared in the form of particles and an open cell foam fulfilling the role of strengthening the matrix. The use of spatial structures of reinforcement provides, in comparison with the strengthening of particles, homogeneity of carbon distribution in the entire volume of the composite. The tests carried out on a pin-disc tester showed that the use of spatial carbon structures in the composite ensures a greater coefficient of friction stability than when reinforcing with particles, and the coefficient of friction with a small proportion of carbon foams (about 1 wt%) is comparable with the coefficient of friction in the contact with composites containing 5-10% carbon particles in granular form.


Sign in / Sign up

Export Citation Format

Share Document