Synergetic Effect of Cryorolling and Postroll Aging on Simultaneous Increase in Wear Resistance and Mechanical Properties of an Al–Cu Alloy

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
I. Jaseem ◽  
R. J. Immanuel ◽  
P. N. Rao ◽  
F. Khan ◽  
B. N. Sahoo ◽  
...  

Aluminum–copper alloy system is extensively used in structural and aerospace applications for its high strength-to-weight ratio, good mechanical and tribological properties. Improving the properties of these alloys would likely widen their application area. In the present work, an attempt has been made to simultaneously enhance the wear resistance and mechanical properties of an Al–Cu alloy, AA2014 by imparting different levels of cryorolling strains and postroll aging treatment. The wear behavior of the material is studied under dry sliding condition by pin-on-disk experiments and mechanical properties are assessed by tensile test. Formation of high fraction of dislocation density and significant refinement of microstructure during cryorolling and nucleation of fine coherent Guinier–Preston (GP) zones of Al2Cu precipitates during postcryoroll aging has led to about 100% increment in the wear resistance of the material. Tensile test results proved that the synergetic effect of cryorolling and aging treatment led to 53% increment in strength (557 MPa) without compromising the material's ductility (22.5%). A detailed investigation on the various mechanisms responsible for the enhanced wear resistance and improved mechanical performance is presented based on the microstructural evidence.

2018 ◽  
Vol 18 (2) ◽  
pp. 111-115
Author(s):  
Hassan Abdoos ◽  
Ahmad Tayebi ◽  
Meysam Bayat

Abstract Due to the increasing usage of powder metallurgy (PM), there is a demand to evaluate and improve the mechanical properties of PM parts. One of the most important mechanical properties is wear behavior, especially in parts that are in contact with each other. Therefore, the choice of materials and select manufacturing parameters are very important to achieve proper wear behavior. So, prediction of wear resistance is important in PM parts. In this paper, we try to investigate and predict the wear resistance (volume loss) of PM porous steels according to the affecting factors such as: density, force and sliding distance by artificial neural network (ANN). ANN training was done by a multilayer perceptron procedure. The comparison of the results estimated by the ANN with the experimental data shows their proper matching. This issue confirms the efficiency of using method for prediction of wear resistance in PM steel parts.


2007 ◽  
Vol 129 (3) ◽  
pp. 586-594 ◽  
Author(s):  
H. Yu ◽  
R. Ahmed ◽  
H. de Villiers Lovelock

This paper aims to compare the tribo-mechanical properties and structure–property relationships of a wear resistant cobalt-based alloy produced via two different manufacturing routes, namely sand casting and powder consolidation by hot isostatic pressing (HIPing). The alloy had a nominal wt % composition of Co–33Cr–17.5W–2.5C, which is similar to the composition of commercially available Stellite 20 alloy. The high tungsten and carbon contents provide resistance to severe abrasive and sliding wear. However, the coarse carbide structure of the cast alloy also gives rise to brittleness. Hence this research was conducted to comprehend if the carbide refinement and corresponding changes in the microstructure, caused by changing the processing route to HIPing, could provide additional merits in the tribo-mechanical performance of this alloy. The HIPed alloy possessed a much finer microstructure than the cast alloy. Both alloys had similar hardness, but the impact resistance of the HIPed alloy was an order of magnitude higher than the cast counterpart. Despite similar abrasive and sliding wear resistance of both alloys, their main wear mechanisms were different due to their different carbide morphologies. Brittle fracture of the carbides and ploughing of the matrix were the main wear mechanisms for the cast alloy, whereas ploughing and carbide pullout were the dominant wear mechanisms for the HIPed alloy. The HIPed alloy showed significant improvement in contact fatigue performance, indicating its superior impact and fatigue resistance without compromising the hardness and sliding∕abrasive wear resistance, which makes it suitable for relatively higher stress applications.


2017 ◽  
Vol 907 ◽  
pp. 3-7
Author(s):  
Hülya Akkan ◽  
Mehmet Şi̇mşi̇r ◽  
Kerim Emre Öksüz

NiTi shape memory alloys have attracted significant interest due to their unique superelasticity and high damping performance. In this work, the effect of SiC particle size on both physical and mechanical properties of NiTi matrix composite was investigated. Ni and Ti powders with particle sizes of 40 µm were used with the SiC addition with varying particle sizes of 20 µm and 40 µm, respectively. Composites of NiTi with 1wt. % SiC were fabricated by powder metallurgy technique. The effects of SiCp addition on hardness, relative density and wear behavior of NiTi composites have been investigated. The samples were examined by scanning electron microscope, for microstructural studies and phase development. The results showed that the distribution of the reinforced particle was uniform. Moreover, as the SiC particle size decreases, hardness and wear resistance increase. It was demonstrated that SiC particle size significantly enhanced the wear resistance of NiTi composite.


2017 ◽  
Vol 264 ◽  
pp. 112-115
Author(s):  
Erfan Suryani Abdul Rashid ◽  
Wageeh Abdulhadi Yehye ◽  
Nurhidayatullaili Muhd Julkapli ◽  
Sharifah Bee O.A. Abdul Hamid

Nanocellulose (NCC) is incorporated into nitrile butadiene rubber (NBR) latex with the composition 0 to 5 phr using dipping method. Mechanical properties of NBR/NCC composites using tensile test was used to characterize their mechanical performance and the fracture surfaces post tensile test were studied. The tensile strength of NBR/NCC composites increase significantly with the addition of nanocellulose. This could be anticipated due to the presence of Van der Waals interaction between hydrophilic natures of nanocellulose with hydrophobic of NBR consequently limits the tearing propagation. The result was supported with the fracture surfaces morphology viewed under Fourier Emission Scanning Electron Microscopy (FESEM).


Author(s):  
Dr. B. Anandavel ◽  
Dr J Anburaj ◽  
Dr K Thillairajan ◽  
V Devakannan

Aim of this research paper is to study the microstructural behavior and mechanical properties of Functionally Gradient (FG) layer of Al-Si alloy castings produced by CDC process. The effect of decantation time on the thickness of functionally gradient castings of Al-4.5 wt % Si alloy as an inner layer and Al-Si alloy with 12.5 wt %Si as outer layers was studied by CDC process. The three different combinations of FGM castings were characterized for microstructural and wear behavior using metallurgical characterization and mechanical testing. From the microstructural and wear behavior of FGM casting at outer layer, FG layer and inner layer, it is observed that the FG layer of FGM casting showed very wear resistance compared to other two layers in the FGM casting.


Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1329
Author(s):  
Pengyan Zhang ◽  
Chi Zhang ◽  
Xiaoguang Zhou ◽  
Zhenyi Huang

Ni-Cr-Mo-based superalloy is widely used as a key component in many critical environments. To ensure that the manufacturing process does not impact the long-term service performance of these components, the aging precipitation behavior at different temperatures and its effect on intergranular corrosion (IGC) resistance and wear resistance of a Ni-Cr-Mo-based C276 superalloy were investigated. The equilibrium phase diagram was calculated first using thermodynamic software to confirm the potential phases. Carbides of M6C were found to be formed at grain boundaries after aging at 800–850 °C for short-term treatment. The other two phases (μ phase and P phase) indicated in the phase diagram were not observed for the samples after aging treatment up to 15 h. Furthermore, double loop electrochemical potentiokinetic reactivation (DL-EPR) tests were conducted to examine the IGC resistance. The degree of sensitization increased with the aging time and severe corrosion was found to occur at grain boundaries. For the first time, the influence of aging treatment on the wear behavior of this superalloy has been specifically studied. Concerning the hot processing of Ni-Cr-Mo-based C276 superalloy, these results indicate the importance of avoiding high-temperature heat treatment for long periods.


2013 ◽  
Vol 6 (2) ◽  
pp. 139-153
Author(s):  
Israa .A.K

This research is devoted to study the effect of addition of different weight percent from SiCp ( 2, 4, 6, 8 ) to Al– 4 Cu alloy which have been fabricated by liquid metallurgy method on the dry sliding wear behavior and mechanical properties. Wear characteristics of Al–SiC composites have been investigated under dry sliding conditions and compared with base alloy. Dry sliding wear tests have been carried out using pin-on-disk wear test under normal applied loads 5, 10, 15 and 20 N and at different sliding velocity of (2.7, 3.7, 4.7) m/sec. It was also observed that the wear rate varies linearly with increases normal applied load but lower in composites as compared to the base material. The wear mechanism appears to be oxidative for both Al – Cu alloy and composites under the given conditions of load and sliding velocity as indicated by optical microscopic of the worn surfaces. Further, it was found from the experimentation that the wear rate decreases linearly with increasing weight percent of silicon carbide. The best results have been obtained at 8 % wt SiC . We also observed that the yield strength, tensile strength increases with increasing wt% of SiC , but the ductility decreases.


2019 ◽  
Vol 71 (9) ◽  
pp. 1064-1071 ◽  
Author(s):  
Alagarsamy S.V. ◽  
Ravichandran M.

Purpose Aluminium and its alloys are the most preferred material in aerospace and automotive industries because of their high strength-to-weight ratio. However, these alloys are found to be low wear resistance. Hence, the incorporation of ceramic particles with the aluminium alloy may be enhanced the mechanical and tribological properties. The purpose of this study is to optimize the specific wear rate and friction coefficient of titanium dioxide (TiO2) reinforced AA7075 matrix composites. The four wear control factors are considered, i.e. reinforcement (Wt.%), applied load (N), sliding velocity (m/s) and sliding distance (m). Design/methodology/approach The composites were fabricated through stir casting route with varying weight percentages (0, 5, 10 and 15 Wt.%) of TiO2 particulates. The mechanical properties of the composites were studied. The specific wear rate and friction coefficient of the newly prepared composites was determined by using a pin-on-disc apparatus under dry sliding conditions. Experiments were planned as per Taguchi’s L16 orthogonal design. Signal-to-noise ratio analysis was used to find the optimal combination of parameters. Findings The mechanical properties such as yield strength, tensile strength and hardness of the composites significantly improved with the addition of TiO2 particles. The analysis of variance result shows that the applied load and reinforcement Wt.% are the most influencing parameters on specific wear rate and friction coefficient during dry sliding conditions. The scanning electron microscope morphology of the worn surface shows that TiO2 particles protect the matrix from more removal of material at all conditions. Originality/value This paper provides a solution for optimal parameters on specific wear rate and friction coefficient of aluminium matrix composites (AMCs) using Taguchi methodology. The obtained results are useful in improving the wear resistance of the AA7075-TiO2 composites.


2019 ◽  
Vol 12 (1) ◽  
pp. 3-13 ◽  
Author(s):  
Guanghui Zhao ◽  
Jijia Zhong ◽  
Y.X. Zhang

Background: Short carbon fibre reinforced epoxy composites have many advantages such as high strength-to-weight ratio, corrosion resistance, low cost, short fabrication time and easy manufacturing. Researches on the mechanical performance of the composites are mainly carried out by means of experimental techniques and numerical calculation. Objective: The study aims to report the latest progress in the studies of mechanical properties of short carbon fibre reinforced epoxy composites. Methods: Based on recently published patents and journal papers, the experimental studies of short carbon fibre reinforced epoxy composites are reviewed and the effects of short carbon fibre on the mechanical properties of the composites are discussed. Numerical studies using representative volume element in simulating macroscopic mechanical properties of the short fibre reinforced composites are also reviewed. Finally, future research of short carbon fibre reinforced epoxy composites is proposed. Results: Experimental techniques, experimental results and numerical simulating methods are discussed. Conclusion: Mechanical properties of epoxy can be improved by adding short carbon fibres. Fiber surface treatment and matrix modification are effective in enhancing interfacial adhesion between fiber and matrix, and as a result, better mechanical performance is achieved. Compared to the studies on equivalent mechanical properties of the composites, researches on the micro-mechanism of interaction between fiber and matrix are still in infancy due to the complexity of both the internal structure and reinforcing mechanism.


2020 ◽  
Vol 16 ◽  
Author(s):  
Nadia A. Ali ◽  
Alaa M. Abd-Elnaiem ◽  
Seenaa I. Hussein ◽  
Asmaa Sh. Khalil ◽  
Hatem R. Alamri ◽  
...  

Objective: In this work, graphene (Gr) or/and Cu particles are used to improve the thermal and mechanical properties of epoxy resin. Methods: Various contents of Gr powder (0.1, 0.3, and 0.5 wt%), Cu powder (10, 30, and 50 wt%) were loaded to epoxy to form Gr/epoxy and Cu/epoxy composites, respectively. In addition, hybrids epoxy/Cu/Gr samples were prepared with a selection of lowest (0.1 and 10) and highest (0.5 and 50) ratios of Gr, and Cu, respectively. Results: The thermal conductivity increases with the increasing weight ratio of Gr and Cu as compared to the pure epoxy. The Thermogravimetric analysis (TGA) of epoxy composites and hybrid composites reveals an improvement in the thermal stability. In addition, the mechanical properties such as hardness shore D and the wear resistance are enhanced for both the epoxy composites and hybrids composites. However, the Ep+0.5wt%Gr+50wt%Cu hybrid composite has the maximum hardness 84, thermal conductivity of 3.84 W/m.K, it shows the lowest wear resistance 2.7×10-6 mm3/Nm at loading 10 N. Conclusion: The hybrid composite containing 0.5wt%Gr and 50wt%Cu shows the maximum hardness and thermal conductivity, as well as the lowest wear resistance when compared to other composites. The physical properties of the hybrid composite can be controlled by the host blend, and hence the morphology, and interfacial characteristics.


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