Micro-X-ray diffraction study of thermal residual stresses in some model aluminum matrix composites

2004 ◽  
Vol 39 (8) ◽  
pp. 2923-2925 ◽  
Author(s):  
Liu Cheng ◽  
Zhang Fan ◽  
Zhang Guoding ◽  
Naka Masaki
Author(s):  
Memduh Kara ◽  
Tolga Coskun ◽  
Alper Gunoz

Aluminum is a material with advantageous properties such as lightness, good conductivity, high plastic deformation ability, and superior corrosion resistance. However, aluminum and many aluminum alloys have disadvantages in terms of mechanical properties such as hardness, tensile strength, and wear resistance. To overcome this disadvantage of aluminum, it is a good method to add ceramic particles to the matrix. For this purpose, in this study, B4C (boron carbide)-reinforced AA2014 aluminum matrix composites were fabricated at 3%, 5%, and 7% reinforcement ratios using the stir casting method. Tensile tests, wear tests, cutting force measurements, and microhardness measurements were performed to determine the fabricated composite materials’ mechanical properties. Scanning electron microscopy and optical microscopy were used to analyze the microstructure of composite. X-ray diffraction analysis was utilized to study the phase identification. As a result of the study, it was observed that with the increase in the B4C reinforcement ratio, the mechanical properties of the aluminum matrix composite material, such as wear resistance, cutting strength, and hardness, increased. On the other hand, the change in tensile strength did not occur in this way. Tensile strength first increased and then decreased. The highest value of tensile strength was achieved at 5% B4C reinforcement. X-ray diffraction results showed that AA2014 and B4C were the fundamental elements in composites and are free from intermetallics.


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.


Metals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 44 ◽  
Author(s):  
Peng-Xiang Zhang ◽  
Hong Yan ◽  
Wei Liu ◽  
Xiu-Liang Zou ◽  
Bin-Bing Tang

In this study, 7075 aluminum matrix composites reinforced with 1.5 wt.% nanosized Al2O3 were fabricated by ultrasonic vibration. The effect of T6 heat treatment on both microstructure and hardness of nanosized Al2O3 reinforced 7075 (Al2O3np/7075) composites were studied via scanning electron microscopy, energy dispersive X-ray spectrometry, X-ray diffraction, transmission electron microscopy, and hardness tests. The Mg(Zn,Cu,Al)2 phases gradually dissolved into the matrix under solution treatment at 480 °C for 5 h. However, the morphology and size of Al7Cu2Fe phases remained unchanged due to their high melting points. Furthermore, the slenderness strips MgZn2 phases precipitated under aging treatment at 120 °C for 24 h. Compared to as-cast composites, the hardness of the sample under T6 heat treatment was increased ~52%. The strengthening mechanisms underlying the achieved hardness of composites are revealed.


2012 ◽  
Vol 567 ◽  
pp. 15-20 ◽  
Author(s):  
Ling Cheng ◽  
De Gui Zhu ◽  
Ying Gao ◽  
Wei Li ◽  
Bo Wang

Alumina reinforced aluminum matrix composites (Al-5wt.%Si-Al2O3) fabricated by powder metallurgy through hot isotactic pressing were sintered in different processes, i.e. solid and liquid phase sintering. Optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscope (SEM), Energy Dispersive X-ray (EDX) techniques were used to characterize the sintered composites. The effects of solid phase and liquid phase sintering on density, microstructure, microhardness, compression and shear strength were investigated. It was found that in situ chemical reaction was completed in solid phase sintering, but the composites had lower microhardness, comprehension and shear strength due to low density and segregation of alumina and Si particles in microstructure. Segregation of reinforcement particles in solid phase sintering resulted from character of solid reaction and Si diffusion at high temperature over a long hold time.


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