Influence Of Friction Stir Processing Research Articles

Influence of friction stir processing (FSP) on arc directed energy deposited 316L stainless steel: a corrosion science study

Friction stir processing (FSP) was employed as a post-printing surface modification technique to enhance surface properties of arc-directed energy deposited 316L austenitic stainless-steel parts. Corrosion properties and passivity of stir zone and base metal were investigated in 3.5 wt.% NaCl solution. Results reveal a gradual improvement in corrosion protection ability of formed passive film on the alloy's surface over time. Specifically, FSPed region exhibited superior passive behavior and uniform corrosion resistance compared to base metal. This improvement was attributed to a more homogeneous microstructure of stir zone, which hindered micro-galvanic coupling effect. However, it was observed that FSP-treatment did not effectively impede the propagation of pitting corrosion.

Influence of Friction Stir Processing on the Hardness and Tribological Properties of Aluminium-Magnesium Alloys

Influence of Friction Stir Processing on the Hardness and Tribological Properties of Aluminium-Magnesium Alloys

Influence of friction stir processing on microstructure and mechanical properties of AA6061 reinforced with Zr and Ni metallic particles

Influence of friction stir processing on microstructure and mechanical properties of AA6061 reinforced with Zr and Ni metallic particles

In-situ induce reinforcement in WAAM of Al-matrix composite using active N2 as shielding gas followed by friction stir processing

Economic and active nitrogen (N2) is used as a shielding gas for the wire-arc additive manufacturing (WAAM) of Al-matrix composite (AMC). Although no crack was found, large flaky nitrides up to 500 μm are generated in the matrix of the Al alloy, leading to a significant deterioration in both plasticity (reduced by 81.4%) and tensile strength (reduced by 17.5%) compared with the deposit protected by argon (Ar), which is to be modified. Then, FSP was performed on the matrix of the Al alloy. The influence of friction stir processing (FSP) on the microstructure and mechanical properties in the stirred zone (SZ) of WAAM 5356 Al alloy deposit, prepared under a N2 environment, was studied. Flaky nitrides were observed in the Al matrix, and were broken due to FSP. The large flaky nitrides with a length of 500 μm were broken into granular nitrides with sizes lower than 2 μm. The grain size in the SZ decreased by 83% after FSP, and the microhardness in the SZ became more uniform, with an average value of 91.9 HV. Owing to the refinement of AlN by FSP, the tensile strength and elongation of the AMC were 349 MPa and 19.9%, much more than that before FSP of 231 MPa and 5.5%, showing an increase of 51.1% and 261.8%, respectively. The plasticity has obvious improvement, which is higher than the common used stir casting AMC.

Influence of friction stir processing on microstructure, mechanical properties and corrosion behaviour of Mg-Zn-Dy alloy

Influence of friction stir processing on microstructure, mechanical properties and corrosion behaviour of Mg-Zn-Dy alloy

Influence of Friction Stir Processing on the Mechanical and Microstructure Characterization of Single and Double V-Groove Tungsten Inert Gas Welded Dissimilar Aluminum Joints

Influence of Friction Stir Processing on the Mechanical and Microstructure Characterization of Single and Double V-Groove Tungsten Inert Gas Welded Dissimilar Aluminum Joints

Influence of Friction Stir Processing on the Friction, Wear and Corrosion Mechanisms of Solid-State Additively Manufactured 316L Duplex Stainless Steel

Friction stir processing (FSP) was employed as a post-surface processing technique to modify the tribological and corrosion behavior of cold-sprayed (CS) 316L SS deposits. Results indicate that the effect of FSP induced an austenitic phase transformation due to the combination of frictional heat and plastic deformation. Consequentially, the friction of the CS deposit after FSP decreased by 8.3%. Similarly, the wear rate was reduced by 55.1%. These properties were improved mostly due to the closure of pores (yielding a 99.97% density) and localized grain refinement. Electrochemical measurements revealed that the corrosion rate was reduced by ∼65%. Also, the pitting corrosion resistance (Epit – Ecorr) increased, which can be majorly attributed to the densified surface and full austenitic phase transformation after FSP. Compared to the other samples, the highest polarization resistance at the corrosion potential (Rpol) was obtained for the FSP CS 316L SS. Based on these findings, it can be inferred that FSP is a viable method to improve the tribological and corrosion behavior of CS 316L SS deposits.

The role of vibration and pass number on microstructure and mechanical properties of AZ91/SiC composite layer during friction stir processing

In this study, nano-sized SiC particles are added to AZ91 magnesium alloy using friction stir processing (FSP) and friction stir vibration processing (FSVP) to produce surface nano-composite layers. FSVP is a modified method of FSP in which the specimen is vibrated during FSP. The influence of FSP and FSVP pass numbers on mechanical and microstructural behaviors of the developed surfaces is investigated. It is indicated that nano-composite layers produced by FSVP have finer microstructures compared to those produced by FSP, and nano-sized particles are distributed more homogeneously. Furthermore, mechanical properties including hardness, scratch resistance, ductility, and strength of FSV processed specimens, were higher than those related to FS processed specimens. The results show a decline in the porosity content as the FSP passes are increased. Also, the compressive strength of the FSVP-ed composites is higher than those for the FSP-ed samples. It is also noticed that an increase in the vibration frequency during the FSVP process causes a more uniform dispersion of composite particles and thus, decreases particle clustering.

Influence of friction stir processing and aging heat treatment on microstructure and mechanical properties of selective laser melted Mg-Gd-Zr alloy

The low ductility of Mg alloy fabricated by selective laser melting (SLM) technique usually restricts its application in several fields. Friction stir processing (FSP) is a promising post-treatment method to solve this problem. A detailed study of how FSP affect pore defects, molten pool boundary, grain morphology, aging precipitates and mechanical properties of SLMed Mg-10Gd-0.2Zr (G10K, wt.%) alloy was conducted. The results show that FSP can lead to porosity reduction from 0.779% to 0.015%, vanishment of molten pool boundary, columnar to equiaxed transition and grain refinement. Thus, a significant enhancement of room temperature tensile properties is reported with a remarkable increase of elongation (EL) from 2.2% to 7.5% without the sacrifice of strength after FSP (while yield strength (YS) and ultimate tensile strength (UTS) increased from 180 MPa, 228 MPa to 202 MPa, 272 MPa respectively). After peak aging heat treatment, the plate aspect ratio and area number density of β' aging precipitates in the FSP-T5 G10K alloy are higher than those of SLM-T5 G10K alloy, resulting in a stronger aging hardening response (hardness increment 28.3 HV versus 22.7 HV). As a result, the FSP-T5 G10K alloy exhibits YS of 285 MPa, UTS of 356 MPa and EL of 1.3%, while those of the SLM-T5 G10K alloy are only 243 MPa, 260 MPa and 0.3%. These findings demonstrate that FSP is very effective for modifying microstructure and enhancing mechanical properties of the SLMed alloys.

Wear and Corrosion Behavior of Cryogenic Friction Stir Processed AZ31B Alloy

This research work investigated the influence of friction stir processing under cryogenic treatment on the wear and corrosion behavior of an extruded AZ31B alloy. The experimental work that employed rotational speeds of 800, 1000, and 1200 rpm have been used, keeping the tool feed rate constant at 60 mm/min. The wear mechanism of the AZ31B alloy and cryogenic friction stir processed specimens were studied using a high magnification of SEM images. A lower wear rate was attained under cryogenic conditions which are around 20% better than the base metal. The results revealed the achievement of a lower corrosion rate at the rotational speed of 1000 rpm. The presence of fine grains and the absence of defects in the processed region lead to higher hardness.

Influence of Friction Stir Processing on Wear, Corrosion, and Fracture Toughness Behavior of 2507 Super Duplex Stainless Steel

Super duplex stainless steels (SDSS) are used in offshore applications and oil/gas plants operating under severe service conditions due to their superior mechanical and electrochemical properties. Fracture toughness, wear and corrosion resistance of a material depends largely on its microstructure and can be improved by refining the latter. Friction stir processing (FSP) can be employed to refine the microstructure of the material, resulting in superior fracture toughness, wear, and corrosion resistance. In the present research, SAF 2507 SDSS was subjected to FSP with optimized processing parameters to study the influence of FSP on fracture toughness, wear, and corrosion resistance of the material. It was observed that FSP refined alloy grains by decreasing the grain size from an average of 160 µm in the base metal to 2-30 µm in the stir zone. Refinement of grains increased the hardness of the material, which enhanced its wear resistance by more than 15%. Wear track and debris analysis revealed the change in wear mechanism of the processed material. FSP also modified the surface composition of processed material, which served to improve its corrosion resistance by more than 80%. Morphology of the corroded surfaces of base and processed material showed that the processed material was more resistant to corrosive attacks than base material. FSP enhanced the grain boundaries in the processed region which improved the fracture toughness after exposure to accelerated corrosion by about 26%. Fractographic study revealed that processed material had brittle fracture behavior while base material had ductile fracture behavior.

Influence of Friction Stir Processing on Weld Temperature Distribution and Mechanical Properties of TIG-Welded Joint of AA6061 and AA7075

The joining of dissimilar materials is required in many engineering and defense applications, and the conventional fusion welding often results in defective welds. The friction stir welding has minimized the welding defects, but not completed. This work focuses on the effect of friction stir processing on TIG-welded joints with filler ER 5356 to improve the mechanical properties of TIG-welded joints. In this paper, the FSP tool pin rotates on an already welded joint by TIG welding to lower the welding load and improve the weld quality by adjusting the processing parameters of friction stir processing. After analyzing the mechanical properties of TIG + FSP-welded joint, computational fluid dynamics-based numerical model was developed to predict the temperature distribution and material flow during TIG + FSP of dissimilar aluminum alloys AA6061 and AA7075 by ANSYS fluent software. The minimum compressive residual stress 18 MPa, maximum tensile strength (281.1 MPa) and hardness (107 HV) were located at the nugget zone of the TIG + FSP weldment at tool rotation speed of 1300 rpm, traverse speed of 30 mm/min and tilt angle 2°. The predicted peak values of temperature at the weld region were calculated and the maximum temperature (505 °C) and maximum heat flux (2.93 × 106 w/m2) were observed at a tool rotation of 1300 rpm.

Effect of Friction Stir Processing on Microstructure and Mechanical Properties of TIG Welded Joint of AA6061 and AA7075

In tungsten inert gas welding (TIG), micro-cracks, porosity, coarse grain structure and high residual stress distribution were found due to persisting thermal conditions. The TIG welded joint is processed using friction stir processing with input process parameters to avoid these defects. In present work, the experimental investigation was conducted to examine the influence of friction stir processing (FSP) on microstructure and mechanical properties of TIG welded joint of AA6061 and AA7075. Tensile test, Vickers hardness test, x-ray diffraction, microscopy and energy-dispersive x-ray test were performed for concluding the optimum set of parameters. The tensile test results shows that the hybrid TIG + FSP welded joint had higher tensile strength than TIG welded joint with filler ER4043, whereas the increment in the micro-hardness of TIG + FSP welded joint was observed. The grain size also decreases when tool pin rotates on TIG welding with different processing parameters. It was found that the maximum tensile stress, % elongation and micro-hardness at nugget zone for TIG + FSP welded joint are 255 MPa, 29.2, and 105 HV respectively. The present investigation demonstrates that the tool rotational speed and traverse speed are the dominating parameters to improve the mechanical properties of TIG welded joint.

Influence of Friction Stir Processing on Mechanical Behavior of 2507 SDSS

Duplex stainless steel (DSS) is used for desalination equipment, pressure vessels, marine applications, offshore applications, and in oil/gas plants where a highly corrosive environment is present. Super duplex stainless steel (SDSS) 2507 has excellent mechanical properties, such as high strength, high toughness, high fatigue life, and high corrosion resistance. Friction stir processing (FSP) is used to refine the grain structure of the processed region such that properties like strength, hardness, fracture toughness, fatigue life, and corrosion resistance are enhanced. In this paper, an optimized friction stir process of 2507 SDSS is carried out to refine the microstructure of the material in order to improve its mechanical properties. Microstructure analysis revealed that grains were refined from a size of around 160 µm in the base material to 2–30 µm in the processed zone. This grain size reduction resulted in improved strength, hardness, and fracture toughness of the material by up to 14%, 11%, and 12%, respectively. However, FSP has reduced the fracture strain by about 30%.

Role of Friction Stir Processing Parameters on the Microstructure and Hardness of ZE41 Mg Alloy: A Taguchi Approach

Abstract In the present study, the influence of friction stir processing (FSP) tool rotational speed and tool travel speed on achieving higher hardness in ZE41 Mg alloy was investigated by adopting a Taguchi design model using orthogonal array. The extent of grain refinement, hardness enhancement, and achieving defect-free stir zones in FSP completely depend on process parameters. In the present work, FSP parameters such as tool rotation speed and tool traverse speed were varied. The microscopic and macroscopic observations revealed that tool speeds of 1,400 rpm with 25 and 50 mm/min feeds were found to be optimal to develop fine grain size and wide stir zone, respectively, without defect. These results are in good agreement with the design model and help with choosing optimized parameters with a minimum number of experiments in developing grain-refined ZE41 Mg alloy for emerging lightweight technological applications.

Friction stir processing of dual phase steel: Microstructural evolution and mechanical properties

The influence of friction stir processing (FSP) on the microstructure and mechanical properties of a DP 600 steel has been studied. The microstructure evolution during the FSP has been characterized using electron back-scatter diffraction (EBSD) technique and scanning and transmission electron microscopes. Standard tension and hardness tests were used to characterize the mechanical properties. The results show that the FSP produced a refined microstructure composed of ferrite, bainite, martensite, and tempered martensite which in turn increased the hardness and strength magnitudes by a factor of 1.5. The initially 2.83 μm average grain size of ferrite has decreased to 0.79 μm in the pin effected zone of (PE-SZ-I) of the processed region. Both EBSD and TEM observations showed regions with high dislocation density and sub-structures region in the processed zone. The grain size became coarser, the density of both dislocations and low-angle grain boundaries decrease, away from the processed zone. Moreover, phase fractions and hardness values were predicted using CALPHAD thermodynamic based software based on commercial material properties. Although the prediction does not take into consideration the influence of severe plastic deformation, the results were within 10% uncertainties of the experimental findings. The present study demonstrates that an ultra-fine grained structure can be obtained through the thickness of a 1.5 mm thick D P600 steel sheet via FSP. FSP can produce a range of different hardness and strength values; which can also be predicted successfully by inputting the composition and local temperatures reached during the FSP.

Study of the influence of friction stir processing on tungsten inert gas welding of different aluminum alloy

Tungsten inert gas welding is the most commonly used process for joining of aluminum alloy, which are highly demanded in aerospace application. In this process coarse grain structure, micro crack and porosity was obtained due to persisting thermal conditions when the fusion zone start to solidify. The formation of these defects on the weld region will result in reduction of weld strength about to half the parent material. To avoid these defects the top surface of gas tungsten arc welding are processed using friction stir processing up to certain depth from the top of the welds. Friction stir processing destroyed the coarse grain dendritic structure in the tungsten welded joint, because of change in grains refinement and microstructure significantly improved the hardness of the friction stir processing (FSP) weld over the base metal and TIG weld. In this study, we compared the experimental result of TIG, FSW and (TIG + FSP) welded joint. Coarse grain structure was observed in TIG welding and fine grain structure was observed in FSP process. In addition very fine grain structure we observed in stir zone due to the effect of intense plastic deformation and temperature during TIG + FSP.

Influence of friction stir processing on microstructure and tensile behavior of AA6061/Al3Zr cast aluminum matrix composites

Friction stir processing (FSP) has emerged as an effective secondary processing technique to improve the microstructure and properties of aluminum matrix composites (AMCs). Al/(0–15 wt.%) Al3Zr AMCs were prepared by adding zirconium powder to molten aluminum and subjected to FSP. The microstructural changes before and after FSP were studied using OM, SEM, EBSD and TEM. Cast composites exhibited coarse grains, segregation, clustering, pores and coarse and sharp-edged polygonal shape particles. The distribution of particles was rearranged into a homogeneous distribution after FSP. Casting defects such as pores were eliminated. The coarse and sharp edged Al3Zr particles were broken into fine size particles. The grain size reduced remarkably due to severe plastic deformation and the pinning effect of reinforced particles. The density of dislocations increased considerably after FSP. The microstructural changes resulted in an improvement of tensile strength and ductility. The possible strengthening mechanisms were reported.

Influence of Friction Stir Process on Microstructure and Tensile Properties of LM28 Hypereutectic Al-Si Alloy

This paper reports an investigation of the influence of friction stir processing (FSP) on the microstructure modification, tensile properties and hardness of as cast hypereutectic LM28 Al-Si alloy, aimed to decrease Si particles size, porosity, and enhancing tensile properties. Intense plastic deformation foisted by FSP resulted in a remarkable breaking up of the coarse eutectic and primary silicon particles into smaller ones, and closure of porosity. The area sizes of the fragmented Si particles decreased from 155.1 μm² to around 49.4 μm², aspect ratio of about 2.86 in the as cast condition decreased to around 1.63 after FSP. Porosity was also drastically reduced from 94 µm ECD, in the as cast condition to as low as 7.1 µm ECD. The strength and ductility of the alloy increased simultaneously after FSP. The increase in the tensile strength and ductility values after FSP, as compare to the as cast alloy was around 1.56, and 4.38 times respectively. The LM28 FS-processed alloy displayed an increase in quality index of around 1.97 times higher, than that of the as-cast alloy. The hardness of the alloy increased from 64.6HV for the as-cast alloy to about 85.74HV after FSP. Enhancement in all the properties was largely related to the pronounced changes of the shape, area size and distribution of the silicon particles along with the reduction of porosity FSP.

Friction stir processing of AlSi10Mg parts produced by selective laser melting

The additive manufacturing (AM) of aluminum alloys promises a performance enhancement of lightweight parts produced using Selective Laser Melting (SLM). Post-processing for AM parts produced using SLM is often an essential step homogenizing their microstructure and reducing as-built defects. In this study, friction stir processing (FSP) was used as a localized treatment on a large surface area of AlSi10Mg parts using multiple FSP tool passes. The influence of FSP on the microstructure, hardness, and residual stresses of both as-built and hot isostatic pressed (HIPed) parts were investigated. FSP transforms the microstructure of parts into an equiaxed grain structure. Microstructure homogenization was achieved consistently over the processed surface after applying a high ratio of tool pass overlap ≥ 60%. FSP of the as-built sample results in the breaking up of the fibrous Si network into nano-scale particles, leading to a more homogeneous distribution of nano-scale Si particles with a subsequent microhardness increase as compared to the HIP + FSP sample. The normal residual stresses measured on the FSP + as-built surface are lower, as compared to the HIP + FSP surface. A microstructure and hardness map was prepared to assist in selecting the optimum FSP parameters needed to achieve the required quality of the final processed parts. This study concludes that FSP could be used as a localized surface treatment to improve the microstructure of both as-built and HIPed AlSi10Mg parts fabricated using SLM.