EFFECTS OF NI ADDITIVE ON FATIGUE AND MECHANICAL PROPERTIES OF AL-CU ALLOY MANUFACTURED USING POWDER METALLURGY (original) (raw)
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Jordan Journal of Mechanical and Industrial Engineering, 2015
Aluminum is widely used in many engineering applications due to its light weight. However, pure aluminum has some weakness in its mechanical properties due to its columnar microstructure with large grain size. The mechanical properties can be improved by different methods, such as cold working, heat treatment, and alloying. This study aims at enhancing the mechanical properties of commercially pure aluminum through the addition of 4% wt. copper. Tensile test, microstructure test, microhardness test, and fatigue test were performed to investigate the effect of the copper addition on the mechanical properties of pure aluminum. The results depicted that copper addition significantly refined the aluminum grain size, which resulted in improved strength and microhardness, i.e., the fatigue strength was enhanced by more than 110% at 107 cycle, and the microhardness was enhanced by 57.9%. © 2015 Jordan Journal of Mechanical and Industrial Engineering. All rights reserved
Comparison of the characteristics of modern aluminum alloys
Industrial laboratory. Diagnostics of materials, 2019
The results of experimental studies of the static strength, fatigue and crack resistance of modern improved aluminum alloys 1163ATV, 1163RDTV, 1441RT1, 1163T, 1163T7, 1161T, V95ochT2, B96-3pchT12., 1973T2 developed at the All-Russian Scientific Research Institute for Aviation Materials (VIAM, Russia); and 2524-T3, 6013-T6 HDT, 2324-T39, C433-T351, 7055-T7751 developed at ALCOA (USA) are presented. Those materials are used in the construction of modern operated and designed aircraft. The experimental data were obtained in testing standard specimens on electro-hydraulic machines MTS (USA), Instron (Great Britain) and Schenk (FRG). The tested specimens were cut from semi-products manufactured according to serial technologies. The mechanical properties of materials under tension (σb, σ0.2, δ), fatigue characteristics, fatigue crack growth rate, stress crack propagation curves under static loading (R-curves), conditionally critical stress intensity factors are determined according to dom...
2016
Résumé The fatigue resistance of an advanced Al-Cu-Li plate alloy (2050) and of conventional alloys 7010 and 2024 is characterized on notched samples (Kt=2.15) with and without an added spark eroded 0.3 mm defect. This characterization is performed in laboratory air, at different frequencies and in vacuum. 2050 always shows a higher fatigue resistance than 7010. The fatigue resistance of 7010 is affected by a relatively coarse constituent particles distribution and a relatively fast fatigue crack growth rate of short cracks. 2024 and 2050 have similar fatigue resistance with no added defect. 2024 offer a slow early fatigue crack growth rate, especially under vacuum.
Materials Science and Engineering: A, 2018
Electron beam melting (EBM) and Selective Laser Melting (SLM) are powder bed based additive manufacturing (AM) processes. These, relatively new, processes offer advantages such as near net shaping, manufacturing complex geometries with a design space that was previously not accessible with conventional manufacturing processes, part consolidation to reduce number of assemblies, shorter time to market etc. The aerospace and gas turbine industries have shown interest in the EBM and the SLM processes to enable topology-optimized designs, parts with lattice structures and part consolidation. However, to realize such advantages, factors affecting the mechanical properties must be well understoodespecially the fatigue properties. In the context of fatigue performance, apart from the effect of different phases in the material, the effect of defects in terms of both the amount and distribution and the effect of "rough" as-built surface must be studied in detail. Fatigue properties of Alloy 718, a Ni-Fe based superalloy widely used in the aerospace engines is investigated in this study. Four point bending fatigue tests have been performed at 20 Hz in room temperature at different stress ranges to compare the performance of the EBM and the SLM material to the wrought material. The experiment aims to assess the differences in fatigue properties between the two powder bed AM processes as well as assess the effect of two post-treatment methods namelymachining and hot isostatic pressing (HIP). Fractography and metallography have been performed to explain the observed properties. Both HIPing and machining improve the fatigue performance; however, a large scatter is observed for machined specimens. Fatigue properties of SLM material approach that of wrought material while in EBM material defects severely affect the fatigue life.
RESEARCH OF FATIGUE AND MECHANICAL PROPERTIES AlMg1SiCu ALUMINIUM ALLOYS
Advances in Science and Technology Research Journal, 2015
The paper is concerned with an analysis of utility and fatigue properties of industrially produced aluminium alloy, specifically EN AW 6061 (AlMg1SiCu), reinforced with the particles of SiC. The following properties were subject to evaluation: microstructure and sub-structure, mechanical characteristics. All of these mechanical properties in pre-and post-equal channel angular pressed (ECAP) state have been studied. The hardness was evaluated by Vickers hardness test at the load of HV10. The significant part the thesis was devoted to the fatigue properties at cyclic load in torsion. The presented results demonstrate well that the combination of fractography and microscopy can give a significant contribution to the knowledge of initiation and propagation crack in the aluminium alloy.
Fatigue performance of additive manufactured metallic parts
Rapid Prototyping Journal, 2013
Purpose -Additive manufacturing technologies such as, for example, selective laser melting (SLM) offer new design possibilities for a wide range of applications and industrial sectors. Whereas many results have been published regarding material options and their static mechanical properties, the knowledge about their dynamic mechanical behaviour is still low. The purpose of this paper is to deal with the measurement of the dynamic mechanical properties of two types of stainless steels. Design/methodology/approach -Specimens for dynamic testing were produced in a vertical orientation using SLM. The specimens were turned to the required end geometry and some of them were polished in order to minimise surface effects. Additionally, some samples were produced in the end geometry ("near net shape") to investigate the effect of the comparably rough surface quality on the lifetime. The samples were tension-tested and the results were compared to similar conventional materials. Findings -The SLM-fabricated stainless steels show tensile and fatigue behaviour comparable to conventionally processed materials. For SS316L the fatigue life is 25 per cent lower than conventional material, but lifetimes at higher stress amplitudes are similar. For 15-5PH the endurance limit is 20 per cent lower than conventional material. Lifetimes at higher stress also are significantly lower for this material although the surface conditions were different for the two tests. The influence of surface quality was investigated for 316L. Polishing produced an improvement in fatigue life but lifetime behaviour at higher stress amplitudes was not significantly different compared to the behaviour of the as-fabricated material. Originality/value -In order to widen the field of applications for additive manufacturing technologies, the knowledge about the materials properties is essential, especially about the dynamic mechanical behaviour. The current study is the only published report of fatigue properties of SLM-fabricated stainless steels.
Influence of Casting Defects on S–N Fatigue Behavior of Ni-Al Bronze
Metallurgical and Materials Transactions A, 2014
Nickel-aluminum bronze (NAB) alloys have been used extensively in marine applications such as propellers, couplings, pump casings, and pump impellers due to their good mechanical properties such as tensile strength, creep resistance, and corrosion resistance. However, there have been several instances of in-service failure of the alloy due to high cycle fatigue (HCF). The present paper aims at characterizing the casting defects in this alloy through X-ray radiography and X-ray computed tomography into distinct defect groups having particular defect size and location. HCF tests were carried out on each defect group of as-cast NAB at room temperature by varying the mean stress. A significant decrease in the HCF life was observed with an increase in the tensile mean stress, irrespective of the defect size. Further, a considerable drop in the HCF life was observed with an increase in the size of defects and proximity of the defects to the surface. However, the surface proximity indicated by location of the defect in the sample was seen to override the influence of defect size and maximum cyclic stress. This leads to huge scatter in S-N curve. For a detailed quantitative analysis of defect size and location, an empirical model is developed which was able to minimize the scatter to a significant extent. Further, a concept of critical distance is proposed, beyond which the defect would not have a deleterious consequence on the fatigue behavior. Such an approach was found to be suitable for generating S-N curves for cast NAB.
Fatigue Behavior of Aerospace Al-Cu, Al-Li and Al-Mg-Si Sheet Alloys
Advanced Materials Research, 2015
In the present work, an experimental study was performed to characterize and analyze the tensile and constant amplitude fatigue mechanical behavior of several aluminum alloys, namely 2024 (Al-Cu), 2198 (Al-Li) and 6156 (Al-Mg-Si). Al-Li alloy was found to be superior of 2024 in the high cycle fatigue and fatigue endurance limit regimes, especially when considering specific mechanical properties. Alloy 6156 was found to have superior constant amplitude fatigue performance that the respective 6xxx series alloys; more than 15% higher endurance limit was noticed against 6061 and almost 30% higher than 6082. Alloy 6156 presented only a marginal increase in fatigue life for the HCF regime.
Fatigue life prediction of the additively manufactured specimen
Modelling and Simulation in Materials Science and Engineering, 2022
Additively manufactured specimens generally exhibit comparable or improved tensile properties, such as yield stress, ultimate tensile strength, and uniform elongation, compared to conventionally manufactured specimens. However, the defects that are typically present in additively manufactured microstructures result in inferior fatigue performance. A representative volume element-based modeling technique incorporating these defects has been used to predict the reduction in endurance limit of an additively manufactured stainless steel compared to the conventionally manufactured material. This physics-based model can clearly demonstrate the poor fatigue performance of additively manufactured specimens based on the micro-plasticity generated by the defects in the microstructure under cyclic loading. A Neuber analytical model has also been applied to predict the fatigue life of additively manufactured materials for a given stress amplitude. Both the prediction from the finite element model and the analytical Neuber model are very close to the experimental endurance limit.
This paper presents the study of different mechanical properties such as Hardness, Tensile strength, Impact strength, Flexural strength, Fatigue strength and Corrosion resistance of newly developed Aluminium-based alloys. The addition of Silicon and Copper will improve the property of the Aluminium alloy. The specimens were prepared with the help of Electric furnace using Stir casting method and the tests were conducted at atmospheric condition. The prepared specimen was subjected to special heat treatment T6 process of 540 0 at 6 hours followed by quenching then cools the specimen for 3 hours in atmospheric condition. After that the annealing process is followed at a temperature of 150 0 at 6 hours. The mechanical properties of Heat treated alloys were improved as compared to the as-cast condition. Also in this kind of alloys may be subjected to use in various applications like Engine bearings, cylinder liner, pistons etc.