scholarly journals Microstructural Evolution and Wear Behavior of SiCp/7085 Composites Manufactured by Ultrasonic Stirring Casting

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 650
Author(s):  
Zhenghua Li ◽  
Ripeng Jiang ◽  
Xiaoqian Li ◽  
Xiang Jia ◽  
Lihua Zhang

In this work, SiCp/7085 composites with a volume fraction of 10% were fabricated by ultrasonic stirring casting. The evolution of the microstructure and wear properties of SiCp/7085 composites, as well as the mechanism of ultrasonic action in the process of preparation, when the ultrasonic treatments last for 0 min, 5 min, 10 min, and 15 min, respectively, were studied using the optical effects (OM), scanning electron microscope (SEM), and X-ray diffraction (XRD). The experimental results show that the high temperature and high pressure formed by the cavitation of ultrasound can effectively eliminate the cluster of particles, improve the distribution of SiC particles, increase the interfacial wettability of the composites, and form MgAl2O4 and MgO on the particle surface, thereby ultimately improving the wear resistance of the composites. Because the particles in the melt are affected by the segregation effect of ultrasonic standing wave field, there exists an optimal value for the ultrasonic treatment time. When the melt is treated with the ultrasonic wave with an amplitude of 12 μm and a treatment duration of 10 min in the test conditions given in this paper, the composites have the most uniform distribution of particles, the best wear resistance, a large and stable friction coefficient, and the minimum weight loss of sample wear: 12 mg. The change of wear resistance is consistent with the variation of solidification structure and interface properties.

Author(s):  
I. Ovali ◽  
H. Karakoç ◽  
H. Çinici

Purpose: In the present study, the effects of B4C reinforcement volume fraction (% 5-15-20)on the abrasive wear properties of AA2024 matrix composites produced with hot pressingmethods were investigated.Design/methodology/approach: As-received samples were also used for comparison.AA 2024 powder was mixed with B4C-SiC-Al2O3 particles by a three dimensional mechanicmixer for 30 minutes. Mixed powder was pressed under 60 MPa at room temperature in thesteel mold by unidirectional. Steel mold kept in the furnace at 550ºC after the pre-pressingfor 30 minutes. Samples were pressed in heated mold under 100 Pa. The wear tests werecarried out using a pin-on-disk wear tester by sliding at sliding speeds of 1.2 m/s againstsilicon carbide paper. Normal loads of 10, 20 and 30 N at constant sliding speed at roomtemperature.Findings: The experimental result showed that B4C volume fraction significantly influencethe wear behavior of AA2024 matrix composites produced with hot pressing methods.Originality/value: It was also found that the wear resistance of AA2024 matrix compositesproduced with hot pressing methods increases with increasing B4C volume fraction.The highest weight loss was obtained in the unreinforced matrix material.


2014 ◽  
Vol 217-218 ◽  
pp. 111-118
Author(s):  
Shu Sen Wu ◽  
Chong Lin ◽  
Shu Lin Lü ◽  
Ping An

The Fe-rich Al-Si alloys have the potential to be used to make wear-resistant parts. However, there has been few work devoted to study the wear behavior of the hypereutectic Al-Si alloys with about 2% Fe (mass %). In this work, the semi-solid slurry of the alloy was prepared by an ultrasonic vibration (USV) process. The effect of Fe content on dry sliding wear properties of the alloys rheo-casted after USV treatment was investigated. The wear tests were carried out using a pin-on-disc wear tester at four different loads of 50N, 100N, 150N and 200N at a constant sliding speed of 0.75m/s. The results show that the wear rate of USV treated alloy increases almost linearly as the applied load increases from 50 N to 200N. The alloys made with semi-solid process exhibited improved wear resistance at the entire applied load range in comparison to the conventional casting alloys. At the applied load of 50N, oxidative wear is the dominant mechanism for the alloys with USV treatment. At 200N, a combination of delamination and oxidation wear is the main wear mechanism. The wear resistance of Al-17Si alloys containing 2% to 3% Fe is closely related to the morphology, size and volume fraction of Fe-bearing compounds, which can be changed by USV semi-solid process.


2021 ◽  
Vol 118 (6) ◽  
pp. 614
Author(s):  
Chellamuthu Ramesh Kumar ◽  
Subramanian Baskar ◽  
Ganesan Ramesh ◽  
Pathinettampadian Gurusamy ◽  
Thirupathy Maridurai

In this research, investigations were carried out on Al6061 base alloy with the changing weight percentage of silicon carbide (SiC) and boron carbide (B4C) with keeping the amount of talc constant. The main objective of this present study was to improve the wear resistance of aluminum alloy using SiC/B4C/talc ceramic particles using stir-casting technique and how the eco-friendly talc content influencing the solid lubricity during the abrasion process. The experiments were conducted via orthogonal array of L27 using Taguchi’s method. The optimum value along with the coefficient of friction was obtained on the basis of grey relational equations and ANOVA, which helped in analysis of most influential input parameters such as applied load, sliding speed, sliding distance and percentage of reinforcement. Conformation tests were performed for the purpose of validation of the experimental results. The specimens were analyzed using scanning electron microscope (SEM) with EDX for micro structural studies. The SiC, B4C and talc presence in the composite helped to improve the mechanical properties, according to the results. The presence of solid lubricant talc as reinforcement to the aluminum hybrid composite reduced the wear properties and decreased the co-efficient friction. These wear resistance improved aluminum metal matrix composites could be used in automobile, defense and domestic applications where high strength and wear resistance required with lesser specific weight.


Author(s):  
Akash Saxena ◽  
Neera Singh ◽  
Bhupendra Singh ◽  
Devendra Kumar ◽  
Kishor Kumar Sadasivuni ◽  
...  

In the present work, phase, microstructure, and wear properties of Al2O3-reinforced Fe–Si alloy-based metal matrix nanocomposites have been studied. Composites using 2 wt.% and 5 wt.% of Si and rest Fe powder mix were synthesized via powder metallurgy and sintered at different temperature schedules. Iron–silicon alloy specimens were found to have high hardness and high wear resistance in comparison to pure iron specimens. Addition of 5 wt.% and 10 wt.% alumina reinforcement in Fe–Si alloy composition helped in developing iron aluminate (FeAl2O4) phase in composites which further improved the mechanical properties i.e. high hardness and wear resistance. Formation of iron aluminate phase occurs due to reactive sintering between Fe and Al2O3 particles. It is expected that the improved behavior of prepared nanocomposites as compared to conventional metals will be helpful in finding their use for wide industrial applications.


Author(s):  
Deepak Mehra ◽  
M.M. Mahapatra ◽  
S. P. Harsha

The purpose of this article is to enhance the mechanical properties and wear resistance of the RZ5 alloy used in the aerospace application by adding TiC particles. The present study discusses processing of in-situ RZ5-TiC composite fabricated by self-propagating high temperature (S.H.S.) method and its wear behavior. The effects of TiC particle on mechanical and microstructural properties of the composite are studied. The wear test is performed by varying the sliding distance and applied load. The composite is characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The results exhibited the properties like strength and hardness of RZ5-10wt%TiC composite has been increased considerably, while grain size is decreased as compared to the RZ5 alloy. The fractography indicated mixed mode (quasi-cleavage and ductile feature) failure of the composites. The wear results showed improvement in wear resistance of the composite. The FESEM showed dominate wear mechanisms are abrasion, ploughing grooves.


2007 ◽  
Vol 539-543 ◽  
pp. 1074-1079 ◽  
Author(s):  
Y.T. Pei ◽  
P. Huizenga ◽  
Damiano Galvan ◽  
Jeff T.M. de Hosson

Advanced TiC/a-C:H nanocomposite coatings have been produced via reactive deposition in a closed-field unbalanced magnetron sputtering system. In this paper, we report on the tribological behavior of TiC/a-C:H nanocomposite coatings in which ultra-low friction is tailored with superior wear resistance, being two properties often difficult to achieve simultaneously. In-situ monitoring the wear depth at nanometer scale reveals that the self-lubricating effects are induced by the formation of transfer films on the surface of ball counterpart. In addition, the CoF of TiC/a-C:H nanocomposite coatings decreases with decreasing relative humidity. This phenomenon can be interpreted in terms of water molecule interactions with the wear track. The influence of the volume fraction and grain size of TiC nanocrystallites on the coating properties has been examined. A superior wear resistance at a level of 10-17 m³/(N m lap) has been achieved under the condition of super-low friction and high toughness, both of which require fine TiC nano-particles (e.g. 2 nm) and a wide matrix separation that must be comparable to the dimensions of the nano-particles.


2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Ridvan Gecu ◽  
Ahmet Karaaslan

This study aims to investigate the effect of volume fraction of commercially pure titanium (CP-Ti) on microstructural, mechanical, and tribological features of A356 aluminum matrix composites. Vacuum-assisted melt infiltration casting was performed to produce composites with 50%, 65%, 75%, and 80% CP-Ti contents. CP-Ti sawdusts were assembled under mechanical pressure in order to attain porous one-piece CP-Ti preforms which were infiltrated by A356 melt at 730 °C under 10−5 Pa vacuum atmosphere. TiAl3 layer was formed at the interface between A356 and CP-Ti phases. Owing to increased diffusion time through decreased diffusion path length, both thickness and hardness of TiAl3 phase were increased with increasing CP-Ti ratio, whereas the best wear resistance was obtained at 65% CP-Ti ratio. The main reason for decrease in wear resistance of 75% and 80% CP-Ti reinforced composites was fragmentation of TiAl3 layer during wear process due to its excessively increased brittleness. Strongly bonded TiAl3 phase at the interface provided better wear resistance, while weakly bonded ones caused to multiply wear rate.


2012 ◽  
Vol 19 (05) ◽  
pp. 1250052 ◽  
Author(s):  
X. H. WANG ◽  
M. ZHANG ◽  
B. S. DU ◽  
S. LI

Iron-based composite coatings reinforced with TiB2–TiC multiple ceramic have been fabricated from a precursor of B4C , TiO2 and Al powders by laser cladding. The effect of TiO2 and Al on the microstructure and wear properties of the coatings was investigated. The results showed that the volume fraction, type and size of the reinforcements were influenced by the content of TiO2 and Al . TiB2 and TiC were evenly distributed in the coating; however, most of Al2O3 were ejected from the coatings, only few of them retained in the coating acting as nucleation core of reinforcement or inclusion. The microhardness and wear resistance of the coatings were improved, whereas the friction coefficients of the coatings were considerably lower than that of substrate.


2017 ◽  
Vol 13 (3) ◽  
pp. 32-36
Author(s):  
S. Rajesh ◽  
C. Velmurugan

Metal matrix composite (MMC) focuses primarily on improved specific strength, high temperature and wear resistance application. Aluminum matrix reinforced with titanium carbide and molybdenum disulfide has good potential and also self-lubrication. The main challenge is to produce this composite in a cost effective way to meet the above requirements. In this study Al–TiC-MoS2 castings with different volume fraction of TiC and MoS2 were produced in an argon atmosphere by an enhanced stir casting method. Hardness of the composite has increased with higher % of TiC addition. At that same time self-lubrication of composite has occur in the effort of MoS2. Dry sliding wear behavior of AMC was analyses with the help of a pin on disc wear and friction monitor. The present analyses reveal the improved hardness  as well as wear resistance.


Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1321 ◽  
Author(s):  
Arnoldo Bedolla-Jacuinde ◽  
Francisco Guerra ◽  
Ignacio Mejia ◽  
Uzzi Vera

From the present study, niobium additions of 1.79% and 3.98% were added to a 15% Cr–3% C white iron, and their effects on the microstructure, hardness and abrasive wear were analyzed. The experimental irons were melted in an open induction furnace and cast into sand molds to obtain bars of 45 mm diameter. The alloys were characterized by optical and electron microscopy, and X-ray diffraction. Bulk hardness was measured in the as-cast conditions and after a destabilization heat treatment at 900 °C for 30 min. Abrasive wear resistance tests were undertaken for the different irons according to the ASTM G65 standard in both as-cast and heat-treated conditions under three loads (58, 75 and 93 N). The results show that niobium additions caused a decrease in the carbon content in the alloy and that some carbon is also consumed by forming niobium carbides at the beginning of the solidification process; thus decreasing the eutectic M7C3 carbide volume fraction (CVF) from 30% for the base iron to 24% for the iron with 3.98% Nb. However, the overall carbide content was constant at 30%; bulk hardness changed from 48 to 55 hardness Rockwell C (HRC) and the wear resistance was found to have an interesting behavior. At the lowest load, wear resistance for the base iron was 50% lower than that for the 3.98% Nb iron, which is attributed to the presence of hard NbC. However, at the highest load, the wear behavior was quite similar for all the irons, and it was attributed to a severe carbide cracking phenomenon, particularly in the as-cast alloys. After the destabilization heat treatment, the wear resistance was higher for the 3.98% Nb iron at any load; however, at the highest load, not much difference in wear resistance was observed. Such a behavior is discussed in terms of the carbide volume fraction (CVF), the amount of niobium carbides, the amount of martensite/austenite in matrix and the amount of secondary carbides precipitated during the destabilization heat treatment.


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