scholarly journals Microstructure and Wear Resistance of TiB2/7075 Composites Produced via Rheocasting

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1068
Author(s):  
Qian Gao ◽  
Bin Yang ◽  
Guisheng Gan ◽  
Yujie Zhong ◽  
Liang Sun ◽  
...  

In this study, TiB2/7075 aluminum matrix composites were prepared via in situ synthesis. It was found that TiB2 particles are mainly quadrate. Large TiB2 particles (1–2 μm) agglomerate at grain boundaries, but most of the particles are on the submicron scale. Adding 4.5 wt.% TiB2 particles effectively optimizes α-Al grains in the 7075 aluminum alloy. By combining in situ reinforcing particles with the self-stirring effect of a serpentuator, rheocasting of the 7075 aluminum alloy was achieved in a simple and economical way. The average grain size of the specimen after rheocasting and heat treatment was smaller than 33 μm, and the shape factors were greater than 0.85. The wear resistance of the 4.5 wt.% TiB2/7075 aluminum matrix composite that was prepared via rheocasting and gravity casting was tested with loads of 30, 60, 90, and 120 N at a friction speed of 0.15 m/s for a duration of 30 min. Because of the optimized microstructure and increased hardness, the wear resistance of the 4.5 wt.% TiB2/7075 aluminum matrix composite was significantly better than that of the 7075 aluminum alloy, and the wear resistance of the rheocast TiB2/7075 aluminum matrix composite was better than that of the gravity cast one.

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1412
Author(s):  
Hansen Zheng ◽  
Zhifeng Zhang ◽  
Yuelong Bai

The requirements of high-strength, wear-resistance and lightweight of brake drums have been continually increasing in recent years and any specific aluminum alloy or particle-reinforced aluminum matrix composites may not satisfy all the demands. Combining dissimilar materials to play their respective advantages is a solution to this problem. In this study, a compound casting method was used to combine solid SiCp/A357 composite and a liquid 7050 aluminum alloy to prepare an aluminum matrix composite with a layered structure. The ProCAST numerical simulation software was used to predict the heat transfer in compound casting process and guide the preheating temperature of the wear-resistant ring in the experiment. An Optical Microscope (OM) and Scanning Electron Microscope (SEM) were used to observe microstructures around the solid–liquid bonding interface, the element distribution and phase component of which were analyzed by Energy Dispersive Spectroscopy (EDS) and mechanical properties were evaluated by microhardness and shear tests. The results showed that the interface of the layered aluminum matrix composite prepared by this method achieved complete metallurgical bonding and a transition zone formed on the solid surface. After T6 heat treatment, the average shear strength of the interface increased from 19.8 MPa to 33.8 MPa.


2020 ◽  
Vol 61 (1) ◽  
pp. 108-111
Author(s):  
A. B. Finkelstein ◽  
A. V. Shak ◽  
A. A. Schaefer

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1213
Author(s):  
Dae-Young Kim ◽  
Pil-Ryung Cha ◽  
Ho-Seok Nam ◽  
Hyun-Joo Choi ◽  
Kon-Bae Lee

The nitridation-induced self-formed aluminum matrix composite (NISFAC) process is based on the nitridation reaction, which can be significantly influenced by the characteristics of the starting materials (e.g., the chemical composition of the aluminum powder and the type, size, and volume fraction of the ceramic reinforcement) and the processing variables (e.g., process temperature and time, and flow rate of nitrogen gas). Since these variables do not independently affect the nitridation behavior, a systematic study is necessary to examine the combined effect of these variables upon nitridation. In this second part of our two-part report, we examine the effect of nitrogen flow rates and processing temperatures upon the degree of nitridation which, in turn, determines the amount of exothermic reaction and the amount of molten Al in the nitridation-induced self-formed aluminum matrix composite (NISFAC) process. When either the nitrogen flow rate or the set temperature was too low, high-quality composites were not obtained because the level of nitridation was insufficient to fill the powder voids with molten Al. Hence, since the filling of the voids in the powder bed by molten Al is essential to the NISFAC process, the conditions should be optimized by manipulating the nitrogen flow rate and processing temperature.


Author(s):  
Basuki Widodo ◽  
Agung Panji Sasmito

Aluminum is a widely used and applied material in daily life or in the industrial and automotive world. In order to improve the performance and properties of the application to be used, it needed an alloying element to improve the mechanical properties of the aluminum. Aluminum Matrix Composite (AMC) or better known as aluminum matrix composite is one type of material that has great potential to be developed, due to its good combination and properties such as high strength and hardness, low density, low density, capable of good machining, and its basic ingredients are easily found on the market and cheaper than other materials. This research was conducted using the stir casting process to be able to mix all the compositions contained in aluminum matrix composites and to help the distribution of alumina reinforcing particles (Al2O3) and aluminum matrices be evenly distributed. The parameters used in this casting process are varying the volume fraction of the Al2O3 amplifier by 0.5%; 1.5% and 2.5% plus the magnesium content remains 0.9%. The results showed that the addition of Al2O3 can increase the value of hardness and reduce the value of tensile strength. The highest hardness value was 75.3 HRB at the addition of Al2O3 by 2.5% and the lowest tensile strength value was 7.17 Kgf / mm2 with the percentage of Al2O3 addition of 0.5%.


Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2024
Author(s):  
Jun Liang ◽  
Chunjing Wu ◽  
Zihang Zhao ◽  
Weizhong Tang

In order to promote the industrialization of the large deformation technology of carbon fiber composites, this paper studies a new method of forming of helical carbon fiber reinforced aluminum matrix composite. The purpose is to solve the problem of large deformation of carbon fiber with low elongation and metal matrix with high elongation. By introducing carbon fiber with helical space structure into the aluminum matrix, the helical carbon fiber reinforced aluminum matrix composites were prepared and the subsequent drawing deformation was carried out. Here we systematically studied the large plastic deformation behavior of helical carbon fiber reinforced aluminum matrix composite via a combination of numerical simulations and experiments, and analyzed the deformation law and stress of helical carbon fiber in the deformation process. We found that the plastic deformation of the composite causes local stress concentration around the helical carbon fiber, and the helical carbon fiber will move synchronously with the aluminum matrix during the deformation, and receive the pressure from the aluminum matrix. Second, the best process parameters obtained from the simulation, that is, the drawing die angle α = 7°, when five-pass drawing experiments were carried out, the total deformation reached 58%, and the average elongation of a single pass was 18.9%. The experimental show carbon fiber reinforced aluminum matrix composite with helical space structure can achieve large deformation and high strength. The experimental and simulation are in general agreement, which verifies the correctness of the carbon fiber helical structure model.


2017 ◽  
Vol 52 (1) ◽  
pp. 123-134 ◽  
Author(s):  
Mohammad Senemar ◽  
Behzad Niroumand ◽  
Ali Maleki ◽  
Pradeep K Rohatgi

In this study, in situ aluminum matrix composites were synthesized through pyrolysis of high temperature vulcanization silicone in commercially pure aluminum melt. For this purpose, 1 to 4 wt% of high temperature vulcanization silicone was added to a vortex of molten aluminum at 750℃ and the resulting slurries were cast in steel dies. Microstructure, hardness, and tensile properties of the as-cast samples were examined at ambient and high temperatures. The results revealed the in situ formation and distribution of reinforcement particles in the matrix. Energy-dispersive X-ray analysis indicated that the formed reinforcement particles consisted of O and Si elements. This confirms the in situ reinforcement formation by pyrolysis of high temperature vulcanization silicone in the melt. The size of the in situ formed particles was mostly in the range of 200–2000 nm. It was shown that the composites synthesized by the addition of 4 wt% high temperature vulcanization had the highest mechanical properties both at ambient and high temperatures. Room temperature hardness, tensile strength, and yield strength of this sample were increased by about 50%, 23%, and 19% compared to the monolithic sample, respectively.


Sign in / Sign up

Export Citation Format

Share Document