Consumable Rods Research Articles

Linear and cylindrical friction stir additive manufacturing (FSAM) of AA6061-T6 by consumable rods: metallurgical structure, wear, and corrosion properties

Linear and cylindrical friction stir additive manufacturing (FSAM) of AA6061-T6 by consumable rods: metallurgical structure, wear, and corrosion properties

Effect of heat treatment before fast multiple rotation rolling on friction surfaced Al–Si–Cu alloy

In this study the effect of combination of heat treatment of consumable rod and solid solution heat treatment before fast multiple rotation rolling (FMRR) processing on microstructure, mechanical property and wear resistance of Al–Si–Cu alloy friction surfaced on commercial pure aluminum alloy were investigated. Results show that after the FMRR process, there is a significant reduction (99% reduction) in the friction surfaced coating surface roughness. The surface roughness after FMRR processing in the coatings created by homogenized and solid solution treated consumable rod is 0.74 ± 0.12, and 0.56 ± 0.08 μm, respectively. In the coating created by homogenized rod the minimum grain size (1.7 ± 0.2 μm) formed in the FMRR processed layer. Using homogenized consumable rod and FMRR processing by rotational speed of 3000 rpm and traverse speed of 140 mm/min, the maximum hardness (9.8 ± 0.3 GPa) and minimum wear rate (4.6 ± 0.1 μg/m) created at processed layer. FMRR processing by rotational speed of 3000 rpm and traverse speed of 140 mm/min, result in 27 and 24 % increasing in hardness at friction surfaced coating created by homogenized and solid solution treated consumable rods, respectively.

Effect of non-isothermal aging on microstructure and corrosion behavior of multilayer friction surfaced Al−Mg−Si alloy with Ag additive

The influence of non-isothermal aging on the microstructure and corrosion behavior of multilayer friction surfaced Al−Mg−Si alloy with different amounts of silver additive was investigated. The silver in 4, 8, and 13 wt.% was inserted into the consumable rods by drilling holes in the cross-section of the consumable rods. The coating microstructure was studied by using light and electron microscopy, the mechanical properties of the coatings were studied by using microhardness and tensile tests, and the corrosion resistance of samples was studied by using electrochemical testing. The results show that the grain size of friction surfaced layers decreases from (1.5±0.3) to (1.0±0.3) µm with increasing the silver additive content from 4 to 13 wt.%. The solute silver in the aluminum matrix increases the precipitation kinetics in the Al−Mg−Si alloy. After non-isothermal aging, the yield and tensile strengths of the silver-containing coating are 50.6% and 43.5% higher than those of the silver-free coating, respectively. Non-isothermal aging treatment reduces corrosion current density and increases corrosion resistance of both samples with and without silver additive. The corrosion resistance of the silver-containing coating after non-isothermal aging is 96.5% higher than that of the silver-free coating.

Effect of initial heat treatment of A390 alloy on microstructure and tribological behavior of friction surfaced coating

In this study, the effect of the A390 alloy consumable rod's three preprocessing heat treatment conditions (homogenization, solid solution, and artificial aging treatment) on the microstructural evolution, mechanical properties, and wear resistance of the friction surfaced coating applied on a commercially pure aluminum alloy substrate was investigated. The results showed that friction surfacing using artificially aged and solid solution-treated consumable rods results in minimum (3.45 ± 0.35 μm) and maximum (5.63 ± 0.25 μm) coating grain sizes, respectively. Friction surfacing using artificially aged treated consumable rods results in smaller, more uniformly distributed Si particles in the coating microstructure. The [111] and [101] directions of most grains in the consumable rod and coating are parallel to the consumable rod axial axis and surfacing direction, respectively. Recrystallization texture components, including Goss and Cube-Twin, are observed in coatings. Compared to the other consumable rods, the coatings fabricated using artificially aged treated consumable rod result in highest hardness (117.62 ± 9.58 HV0.1), maximum bond strength (13.98 ± 1.02 kN), and lowest wear rate (5.6 ± 0.8 μg/m).

Effect of preprocessing heat treatment of the Al-16Si-4Cu alloy on microstructure and tribological behavior of friction-surfaced coating

This study investigated the simultaneous effect of the consumable rod's preprocessing heat treatment conditions (homogenization, solid solution, and artificial aging treatment) and severe plastic deformation on the properties of Al-Si-Cu alloy friction surfaced on a commercially pure aluminum alloy substrate. The friction-surfaced coating's microstructural evolution, mechanical properties, and wear resistance were evaluated. The results showed that coatings fabricated using artificially aging (T6)-treated consumable rods resulted in the highest coating width (17.02±0.83 mm) and maximum efficiency (39.78 ± 1.23 %). Friction surfacing using artificially aged and solid solution-treated consumable rods results in minimum (2.78 ± 0.28 µm) and maximum (6.32±0.34 µm) coating grain sizes, respectively. Friction surfacing using T6-treated consumable rods results in smaller, more uniformly distributed Si particles in the coating microstructure. Compared to the other consumable rods, the coatings fabricated using T6-treated consumable rods result in the highest hardness (110.54±10.29 HV0.1), maximum bond strength (14.15±0.75 kN), and lowest wear rate (0.20±0.03 µg/Nm).

Radius of Contact During Friction Surfacing of Stainless Steel 304L: Effect of Spindle Speed and Rod Diameter

Abstract The “radius of contact” or the “real-rotational contact plane,” has been increasingly mentioned terminology in friction surfacing. However, the fundamental understanding of the flow dynamics behind this phenomenon is still very limited. The goal of this study was to understand the influence of spindle speed and consumable rod diameter on the flow dynamics and the radius of contact during friction surfacing of 304L stainless steel over a substrate of the same material. Friction surfacing was performed using consumable rods with diameters of 4.76 mm, 9.52 mm, and 12.7 mm while using spindle speeds from 1500 rpm to 20,000 rpm. The impact of spindle speed on deposition morphology, including the radius of contact, was studied. The radius of contact was calculated empirically and was found to be inversely proportional to the tangential velocity of the rod. The coupling between flow stresses and localized forces is hypothesized to be the key factor behind the variation of the radius of contact with processing conditions.

Characterization of mechanical and metallurgical properties of AA6063 foam developed by friction stir precursor deposition technique

The aim of this work is to develop the precursor-based Al foam by deposition of AA6063-T6 consumable rod, filled with a foamable mixture of titanium hydrate (TiH2) and aluminium powder over a mild steel substrate through friction stir deposition (FSD) technique. The AA6063-T6 consumable rods were drilled with different hole strategies ranging from 1 to 6 holes on the periphery of the rod, which were filled with foaming powder of the same composition. To perform the deposition, a conventional vertical milling machine was used. The deposited material presents a fine equiaxed grain whose size is much lower than the as-received material, indicating dynamic recrystallization during friction stir deposition. The results also show that the foaming particles decrease the hardness values of the produced deposits when compared to those of base material. It has been observed that 4 and 5 numbers of holes in the consumable rod are more suitable for foam development and the foaming particles are more uniform as obtained from energy dispersive spectrum (EDS) and scanning electron microscope (SEM) analysis. It is also observed that by increasing the number of holes in the rod more than 5 promote the formation of defects in the developed foam. The consumable rod with 4 and 5 holes shows the linear plateau stress in the compressive test as compared to 1, 2, 3 and 6 holes.

Microstructure and corrosion behavior of friction-surfaced 304L austenitic stainless steels

Friction surfacing is a solid-state deposition process that provides microstructural and mechanical property benefits over fusion-based deposition methods as a result of the lower heat input and hot working. The study examines microstructure and corrosion properties for friction-surfaced 304L stainless steel consumable rods on 304L stainless steel substrates. Microstructural characterization revealed fine-grained microstructure with distributed strain-induced martensite and high residual compressive stresses. Corrosion studies of friction-surfaced specimens were carried out by exposure to FeCl3 and MgCl2 solutions per ASTM G48 and ASTM G36 standards, respectively. The corrosion tests showed friction surfacing led to shallower and smaller pits than the uncoated substrate, however, the pit number density was higher in the friction-surfaced specimens. The microstructural transformations during friction surfacing are beneficial to mitigating pitting corrosion and potentially chloride-induced stress corrosion cracking (CISCC).

Effect of friction surfacing parameters on microstructure and mechanical properties of solid-solutionized AA2024 aluminium alloy cladded on AA1050

The present study aims to investigate the effect of friction surfacing parameters on the mechanical properties and microstructure of coating fabricated by a solid solutionized consumable rod on the AA1050 substrate. In this regard, the AA2024 aluminum alloy consumable rod was friction surfaced on AA1050 substrate by the rotational speed of 600–1000 rpm, axial feeding rate of 75–200 mm/min, and traverse speed of 100–150 mm/min. The microstructure and mechanical characteristics of coatings showed that increasing the rotational speed, traverse speed, and axial feeding rate results in increasing the unbonded zone extent at the interface of the coating and the substrate. The solid solutionized consumable rod leads to a coating with less width and height in all friction surfacing parameters compared to coatings fabricated by a rod with T3 heat treatment conditions. The average grain size of the coating decreases with decreasing axial feeding rate, increasing traverse speed, and decreasing rotational speed. Although friction surfacing can significantly weaken the fiber texture of consumable rods, the texture intensity in the coatings is slightly changed by changing the friction surfacing parameters. The competitive effect of precipitation hardening and grain refinement mechanisms has a decisive role in the hardness and strength of the coating; however, the influence of the strengthening mechanism through precipitates is much stronger than other mechanisms. Coating fabricated by rotational speed, traverse speed, and axial feeding rate of 1000 rpm, 100 mm/min, and 75 mm/min, respectively, results in the maximum hardness (122.21 VHN0.1) and shear strength (195.65 MPa).

Effects of pre-heat treatment of the consumable rod on the microstructural and mechanical properties of the friction surfaced Al-Cu-Mg alloy over pure aluminum

In this study, the effects of the traverse speed and the pre-heat treatment of the AA2024 consumable rod on the mechanical and microstructural properties of the friction surfaced coating over AA1050 aluminum are investigated. The mechanical and microstructural properties of the coatings are characterized using optical and scanning electron microscopy, macrotexture measurement using X-ray diffraction, and the shear punch test. The results show that in both coatings fabricated by solid solutionized and T3-treated consumable rods, by increasing the traverse speed, the deposition rate decreases, leading to a reduction in the volume of the deposited material. Moreover, the T3 heat treatment of the consumable rod results in a smaller grain size in the coating. Regardless of the consumable rod's pre-heat treatment conditions, the size of the Al2CuMg precipitates in the coating increases by increasing the traverse speed. Friction surfacing using a solid solutionized consumable rod increased and decreased the shear and recrystallization texture in the coating, respectively. The smaller grains, fine precipitates, and a stronger recrystallization texture in the coatings fabricated by T3-treated consumable rod led to higher levels of strength and hardness in these coatings.

An experimental study on friction surfaced coating of Aluminium 6063 over AISI 316 stainless steel substrate

This experimental work was designed to produce a solid state cladding of Aluminium 6063 over AISI 316 stainless steel using friction surfacing. Various parametric combinations considered as the supreme aspects for bonding integrity were used. Successful analysis was made on aluminium coating over stainless steel substrate. The coating strength and bonding integrity were tested taking consumable rods unit dimensions of 14 mm, 18 mm and 22 mm. The deep influence of the axial force and the rotational speed on coating thickness and width was seen. Temperature profile was measured using an infrared thermometer and peak temperature recorded for 14 mm, 18 mm & 22 mm diameter rods were 326 °C, 348 °C and 366 °C respectively. The mechanical bonding strength was examined through vickers micro hardness and bending rest. Hardness value of 138HV and bending strength of 3.2 tons at 90° bent angles were the highest for a 18 mm rod. Analysis of micro structure and interfacial features of the coating using FE-SEM and EDAX techniques showed good molecular interlocking between aluminium and iron particles.

Effects of Friction Surfacing on the Characteristics of Consumable Rods of Ti-6Al-4V

Friction surfacing (FS) is a coating technique applied mainly in corrosion protection and repair of components. The study addresses the effects of deposition and rotational speeds on the rods characteristics and process efficiency for the deposition of Ti-6Al-4V on self-mating substrates by FS. The consumption rate was 1.8 mm/s, deposition speeds of 8, 16 and 24 mm/s and rotational speeds of 2000, 3000 and 4000 rpm. It was shown that the flash forms primarily at the rod, ascending around the tip and leaving the coating without flash. The higher deposition speeds led to a decrease in rod thickness and diameter. For higher rotational speeds, an increase in diameter and decrease in thickness is observed for the flash on the rod. Experiments have shown that the rotational and deposition speeds have a decisive influence on the flash formation. Its microstructure changes due to the welding process and a change in hardness can be observed.

Fabrication of stainless steel 316L/TiB2 composite coating via friction surfacing

Stainless steel 316L/TiB2 composite coatings were fabricated with different TiB2 contents using friction surfacing (FS) on the stainless steel 304 substrate. One or two blind holes were drilled at different positions axially on the cylindrical 316L consumable rods for keeping micron-size TiB2 powder as the reinforcement in the coatings. After FS, TiB2 was found to be embedded into the austenitic matrix and also partially decomposed leading to the formation of FeB2 and FeTi under high temperature and high strain rate. Compared with the friction-surfaced (FSed) 316L coating, the grain size of austenite in the TiB2 reinforced composite coating was refined from 7.8 to 0.64 μm, where austenite grains closed to {111} tends to transform to FeTi. Compared with monolithic 316L coating, the hardness of the FSed 316L/TiB2 coating was significantly increased from 219 to 1056 HV0.2 owing to the presence of TiB2 and intermetallic phases, finer austenitic grains and higher misorientation density. The pitting corrosion resistance of the FSed 316L coating was improved due to the elimination of MnS inclusions whereas the FSed 316L/TiB2 coating possessed lower pitting resistance due to the presence of FeTi. Moreover, the passivity of the 316L/TiB2 coating in 3.5% NaCl solution was preserved but the capability of re-passivation was degraded.

Application of Friction Surfacing to the Production of Aluminum Coatings Reinforced with Al2O3 Particles

The aim of this work was to produce deposits of AA6351-T6, reinforced with alumina (Al2O3) particles, over a substrate of AA5052-H32 through friction surfacing. AA6351-T6 consumable rods were drilled with one and two holes, which were filled with Al2O3 particles posteriorly. To perform the deposition, a conventional KONE KFE-3/BR milling machine was used. The results showed that Al2O3 particles increase the hardness values of the produced deposits when compared to those without particle addition. The coatings presented a fine equiaxed grain size distribution, once the grain refinement was nearly 48% lower than the as-received material. Moreover, deposit regions that showed finer grain boundaries also showed a higher volume fraction, which can be related to the particle stimulated phenomenon. Electron backscatter diffraction results showed the occurrence of low angle grain boundary substructures and lattice rotation, indicating that the material undergoes dynamic recrystallization during friction surfacing.

Influence of friction surfacing process parameters to deposit AA6351-T6 over AA5052-H32 using conventional milling machine

Superficial and microstructural characterization of the deposits was investigated. The substrate/deposit interface resistance was also investigated by bending tests and evaluating the microhardness profile. Consumable rods were deposited perpendicular to the plate rolling direction (DL); the rod rotation during the friction surfacing process was always clockwise and at room temperature. The control parameter deposition process was by the rod feed rate. Microscopic analysis has revealed the microstructural gradient transformation of the consumable rod during the friction surfacing process. Microhardness profile obtained along the rod has highlighted the presence of three distinct forming regions on the consumable material. Friction surfacing produced microstructural deposits of refined grains with 24.1% lower hardness values than those of the consumable material as received. The bending tests revealed delamination presence in the deposit/substrate interface with lower predominance for the 1A deposition process. The combination of the travel speed of 4mm/s and the increased rod feed rate (>5.7mm/s) can increase the adhesive strength of the deposit/substrate interface.

Microstructures of Friction Surfaced Coatings – a TEM Study

Abstract The microstructures of dissimilar metal welds between 9Cr-1Mo (Modified) (P91) and austenitic stainless steel (AISI 304) with Ni-based alloy interlayers (Inconel 625, Inconel 600 and Inconel 800H) are reported. These interlayers were deposited by the friction surfacing method one over the other on P91 alloy, which was finally friction welded to AISI 304. In this paper, the results of microstructural evolution in the friction surfaced coated interlayers (Inconel 625, 600, 800H) are reported. For comparative purposes, the microstructures of consumable rods (Inconel 625, 600, 800H) and dissimilar metal base metals (P91 and AISI 304) were also reported. Friction surfaced coatings exhibited dynamic recrystallization. In friction surfaced coatings, the carbide particles were found to be finer and distributed uniformly throughout the matrix, compared to their rod counterparts.

Feasibility Study of Friction Surfaced Coatings over Non-ferrous Substrates

The present work examines the feasibility of getting friction surfaced coatings on different combinations of consumable rods and non-ferrous substrates. Aluminium (AA1050A), Copper, Stainless Steel (AISI 304), Mild Steel were used as substrates and commercially pure Copper and Stainless Steel (AISI 304) were used as consumable rods. Friction surfacing was carried out using these consumable rods and substrate combinations with a conventional universal milling machine FNU2213. The investigation revealed that certain combinations metallurgically bonded coating is formed quickly over the substrate while with certain other combinations, this coating is formed with the assistance of a start-up plate. However, for a certain combination of parameters, no coating is formed whatsoever. The formation of coating is influenced by the coefficient of friction as well as material properties, such as, thermal conductivity and stability at high temperature.

Effect of Process Parameters on Friction Surfaced Coating Dimensions

Friction surfacing is a novel technology to build corrosion and wear resistant coatings and build functionally graded metallic layers. In this work, the coating dimensions as affected by process parameters and high temperature strength of consumable rods have been compared. Friction stir welding equipment, RM-1 model procured from MTI was used. Carbon steel, austenitic stainless steel and Ni-based alloy coatings were deposited. Following process parameter ranges were used: rotational speed: 1000-2000 RPM, feed rate: 50-150 mm/min and axial load: 3-12 kN. Results showed that the coating width and thickness decreased with a) increased magnitude of the process parameters used and b) increased high temperature strength of the consumable rod.

Friction Freeform Fabrication of Superalloy Inconel 718: Prospects and Problems

Friction Freeform Fabrication is a new solid-state additive manufacturing process. The present investigation reports a detailed study on the prospects of this process for additive part fabrication in superalloy Inconel 718. Using a rotary friction welding machine and employing alloy 718 consumable rods in solution treated condition, cylindrical-shaped multi-layer friction deposits (10 mm diameter) were successfully produced. In the as-deposited condition, the deposits showed very fine grain size with no grain boundary δ phase. The deposits responded well to direct aging and showed satisfactory room-temperature tensile properties. However, their stress rupture performance was unsatisfactory because of their layered microstructure with very fine grain size and no grain boundary δ phase. The problem was overcome by heat treating the deposits first at 1353 K (1080 °C) (for increasing the grain size) and then at 1223 K (950 °C) (for precipitating the δ phase). Overall, the current study shows that Friction Freeform Fabrication is a very useful process for additive part fabrication in alloy 718.

Friction surfacing on nonferrous substrates: a feasibility study

This work reports a feasibility study on producing friction surfaced coatings on nonferrous substrates. Commercially pure aluminum, copper, magnesium (ZM21), Inconel 800, and titanium alloy (Ti-6Al-4 V) were chosen as the substrates. Low carbon steel, aluminum alloy (AA6063), commercially pure copper and titanium were chosen as the consumable rods. Friction surfacing was attempted with all consumable rods on every substrate. In some cases metallurgically bonded coating was obtained readily over the substrate and in some other cases coating was obtained with a start-up plate. However, for certain combination of parameters, no coating could be obtained. The coatings obtained were analyzed for their microstructural features and interfacial characteristics using optical and scanning electron microscopy. The results showed that co-efficient of friction, material properties like thermal conductivity, and stability at high temperature influenced the formation of a coating. Coatings obtained exhibited fine grained microstructure with properties better than the original parent material. Dynamic recrystalization as a result of severe plastic deformation accounts for grain refinement.