| 1. |
- Arya, Pradyumn Kumar, et al.
(författare)
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Development of high strength and lightweight Ti6Al4V5Cr alloy : Microstructure and mechanical characteristics
- 2024
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Ingår i: Journal of Materials Research and Technology. - : Elsevier Editora Ltda. - 2238-7854 .- 2214-0697. ; 28, s. 3526-3540
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Tidskriftsartikel (refereegranskat)abstract
- This article explains development of high strength and lightweight Ti6Al4V5Cr alloy by μ-plasma powder additive manufacturing (μ-PPAM) process for automotive, aerospace, military, dies and moulds, and other similar applications. Microstructure, formation of phases, porosity, microhardness, tensile properties, abrasion resistance, and fracture toughness of multi-layer deposition of Ti6Al4V5Cr alloy are studied and compared with Ti6Al4V alloy. Results reveal that the presence of chromium in Ti6Al4V5Cr alloy refined the grains of its β-Ti and α-Ti phases, increased volume % of β-Ti phase, and promoted formation of its equiaxed grains. It also increased tensile strength, microhardness, abrasion resistance, and fracture toughness of Ti6Al4V5Cr alloy. It enhanced solid solution strengthening and formed higher hardness imparting intermetallic Cr2Ti phase and changed fracture mode to mixed ductile and brittle mode with larger size dimples, cleavage facets, and micropores. But it decreased formation temperature of β-Ti phase and % elongation as compared to Ti6Al4V alloy. Chromium and vanadium content in β-Ti phase of Ti6Al4V5Cr alloy is 7 % and 2.1 % more than its α-Ti phase. This study demonstrates that inclusion of limited amount of chromium content to Ti6Al4V5Cr alloy by μ-PPAM process is very beneficial to enhance microstructure, mechanical properties, crack propagation resistance, and abrasive wear resistance of the Ti6Al4V5Cr alloy. It makes Ti6Al4V5Cr alloy very useful in many commercial applications that require higher strength than Ti6Al4V alloy along with lightweight requirement.
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| 2. |
- Kumar Wagri, Naresh, et al.
(författare)
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Investigation on the performance of coated carbide tool during dry turning of AISI 4340 alloy steel
- 2023
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Ingår i: Materials. - : MDPI. - 1996-1944. ; 16:2
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Tidskriftsartikel (refereegranskat)abstract
- The machinability of materials is highly affected by their hardness, and it affects power consumption, cutting tool life as well as surface quality while machining the component. This work deals with machining of annealed AISI 4340 alloy steel using a coated carbide tool under a dry environment. The microhardness of annealed and non-annealed workpieces was compared and a significant reduction was found in the microhardness of annealed samples. Microstructure examination of the annealed sample revealed the formation of coarse pearlite which indicated a reduction of hardness and improved ductility. A commercially CVD multilayer (TiN/TiCN/Al2O3/ZrCN) coated cemented carbide cutting tool was employed for turning quenched and tempered structural AISI 4340 alloy steel by varying machining speed, rate of feed, and depth of cut to evaluate the surface quality, machining forces, flank wear, and chip morphology. According to the findings of experiments, the feed rate possesses a high impact on surface finish, followed by cutting speed. The prominent shape of the serrated saw tooth chip was noticed at a higher cutting speed. Machined surface finish and cutting forces during turning is a function of the wear profile of the coated carbide insert. This study proves that annealing is a low-cost and economical process to enhance the machinability of alloy steel.
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| 3. |
- Chaudhary, Bhavesh, et al.
(författare)
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Exploring temperature-controlled friction stir powder additive manufacturing process for multi-layer deposition of aluminum alloys
- 2022
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Ingår i: Journal of Materials Research and Technology - JMR&T. - : Elsevier. - 2238-7854. ; 20, s. 260-268
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents preliminary study on multi-layer deposition of aerospace grade Al 6061 alloy by novel friction stir powder additive manufacturing process. Minimum temperature of deposition was in-situ maintained using close loop temperature-controlled system for minimizing thermal gradient in the build direction. Maximum temperature during the deposition was monitored in-situ using pyrometer and thermal imaging camera. Use of a tool with circumferential and radial grooves and continuous external heating facilitated smooth three-layer deposition of Al 6061 alloy with 60% deposition efficiency and 417 degrees C as maximum deposition temperature. Larger value of temperature at deposition zone improved material flowability and deposition quality. Microstructure of multi-layer deposition found to consist of fine sub-grains. Element analysis showed uniform distribution of major alloying elements in it. Phase analysis revealed Al along with Mg2Si hardening precipitates. Tensile strength and microhardness were close to the commercially available wrought AA6061-T4 alloy. It showed ductility with 16% elongation. The presented process is a viable alternative to fusion-based additive manufacturing processes for multi-layer depositions of aerospace grade and other lightweight alloys which are difficult-to-additively-manufacture.
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| 4. |
- Chaudhary, Bhavesh, et al.
(författare)
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Friction stir powder additive manufacturing of Al 6061 alloy : Enhancing microstructure and mechanical properties by reducing thermal gradient
- 2023
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Ingår i: Journal of Materials Research and Technology. - : Elsevier. - 2238-7854 .- 2214-0697. ; 26, s. 1168-1184
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Tidskriftsartikel (refereegranskat)abstract
- Additive manufacturing of Al alloys by fusion-based processes often leads to higher thermal gradients along the build direction resulting in anisotropy, and solidification-related defects such as porosity, hot-cracking, and lack of inter and intra-layer fusion. Therefore, this paper focuses on solid state multi-layer manufacturing of Al 6061 alloy by friction stir powder additive manufacturing (FSPAM) process and enhancing its microstructure and mechanical properties through reduction of thermal gradient along the build direction by maintaining the substrate close to its artificial aging temperature using external heat source in a close-loop with it. The continuous dynamic recrystallization along with reduced thermal gradient led to homogenous microstructure, fine and equiaxed grains of Al 6061 alloy multi-layer deposition. The inherent compressive forces in FSPAM process promoted intimate contact among the powder particles presenting 0.19% porosity. Energy dispersive spectroscopy showed absence of agglomeration of alloying elements due to better mixing of feedstock material beneath the tool. Phase analysis revealed presence of Al and hardening phase Mg2Si with slight shifting of peaks towards higher angle indicating compressive residual stresses. Tensile properties and microhardness of Al 6061 alloy are closer to AA6061-T4 and better than AA6061-O alloy. Reduced thermal gradient contributed to minimal variations in microhardness (8.8%) along the build direction. Fracture morphology analysis exhibited a significant number of dimples indicating ductile nature of Al 6061 alloy with 16.7% elongation. The study presented a new approach for manufacturing Al alloys using their feedstock in powder form and with improved microstructure and mechanical properties.
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| 5. |
- Chaudhary, Bhavesh, et al.
(författare)
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Friction stir powder additive manufacturing of Al 6061/FeCoNi and Al 6061/Ni metal matrix composites : Reinforcement distribution, microstructure, residual stresses, and mechanical properties
- 2023
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Ingår i: Journal of Materials Processing Technology. - : Elsevier. - 0924-0136 .- 1873-4774. ; 319
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Tidskriftsartikel (refereegranskat)abstract
- Fusion based additive manufacturing (FBAM) of second, sixth, and seventh series Al alloys and their metal matrix composites (MMC) is difficult due to their higher thermal conductivity and solidification related problems namely porosity, cracks, thermal distortion, and formation of undesired phases. This paper presents friction stir powder additive manufacturing (FSPAM) process as a promising alternative to overcome these problems in producing multi-layer depositions of Al 6061 based MMCs namely Al 6061/6wt%FeCoNi and Al 6061/6wt%Ni. Their microstructure, distribution and elemental mapping of reinforcement particles, phase analysis, residual stresses of the MMCs and their correlation with microhardness, tensile strength, and fretting wear characteristics are investigated. Material accumulation on their advancing side was minimized by changing tool rotation direction in consecutive layers which produced smoother surfaces on both sides of their deposition. FSPAM made multi-layer depositions of Al 6061/FeCoNi and Al 6061/Ni MMCs have uniform distribution of reinforcement particles, good bonding between layers without cracks and defects, refined and equiaxed grains facilitated by dynamic recrystallization and pinning effect of reinforcement particles, compressive residual stresses of 39 and 48 MPa, no formation of deleterious intermetallic compounds due to absence of melting of matrix and reinforcement, and bowl-shaped substrate-deposition interface. Microhardness and ultimate tensile strength of the MMCs improved by 11.3% and 22.3%, and 30.5% and 31.5% respectively than Al 6061 alloy depositions, their wear resistance enhanced significantly, but % elongation reduced. This study proves FSPAM to be a potential alternative to FBAM processes for better quality multi-layer deposition of Al alloy-based MMCs.
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| 6. |
- Chaudhary, Bhavesh, et al.
(författare)
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Progress in solid-state additive manufacturing of composites
- 2024
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Ingår i: Solid State Additive Manufacturing. - : Taylor & Francis Group. - 9781032616025 ; , s. 127-168
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Bokkapitel (refereegranskat)abstract
- Aluminum-based metal matrix composites have a wide range of applications in the automotive and aerospace industries due to their high strength-to-weight ratio. They are difficult to manufacture using fusion-based additive manufacturing (FBAM) processes because of solidification problems such as thermal stresses, hot cracks and porosity. Moreover, the formation of undesired phases at high temperature creates anisotropy in the composites. To overcome these problems, promising solid-state additive manufacturing (SSAM) processes such as ultrasonic AM, cold-spray AM, friction stir AM, and additive friction stir deposition have been developed. These solid-state processes introduce a novel concept for AM where material is added layer by layer in the solid state by maintaining the maximum temperature below the melting point of feedstock material. These processes have demonstrated the uniform distribution of reinforcing particles, fine-grained microstructure along with good bonding of layers which can offer improved scope for Industry 4.0 applications. This chapter summarizes progress in the SSAM of composites with an emphasis on aluminum-based composites. In addition, various challenges and future work have been briefly discussed which would be helpful to the researchers and industrialist working in the field of SSAM of composites.
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| 7. |
- Patel, Mahesh, et al.
(författare)
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Enhancement of tensile and fatigue properties of hybrid aluminium matrix composite via multipass friction stir processing
- 2022
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Ingår i: Journal of materials research and technology. - : Elsevier. - 2238-7854. ; 21, s. 4811-4823
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Tidskriftsartikel (refereegranskat)abstract
- In present work, friction stir processing (FSP) has been used to fabricate hybrid aluminium matrix composite (HAMC) using a mixture of 6% ZrO2 and 6% Ni as reinforcement particles. Four different passes (1, 2, 4, and 6) were used to study the influence of multipass FSP on tensile properties, residual stresses, and fatigue performance of HAMCs. Six pass FSP led to significantly improved tensile properties due to more uniform distribution of reinforced particles and refined grains, and enhanced compressive residual stresses to-106 +/- 6.8 MPa compared to-9 +/- 1.8 MPa in base material. The increment in fatigue life of HAMCs is 31% (two passes), 61% (four passes), and 69% (six passes) as compared to the base material (4.08 x 105 cycles) for the lowest maximum applied stress of 100 MPa. The fatigue fracture characteristics of HAMCs with more than one FSP pass were found to be ductile-brittle mixed mode. The study concluded better fatigue life of (c) 2022 The Author(s). Published by Elsevier B.V.
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