Multi-pass Friction Stir Processing Research Articles

Effect of processing sequences in multi-pass friction stir processing on microstructure, microtexture and microhardness of 6063 aluminum alloy

ABSTRACT Single and double direction stir processing sequences were employed and investigated by fixing all other FSP parameters. Optical microscopy (OM) was utilised to assess the size and geometry of the processed zone. EBSD was also employed to evaluate the microstructure and microtexture development in different regions of the processed zones. In addition, Vickers microhardness measurements were made to evaluate the hardness evolution across the processed zone for the two processing sequences. The results show that using a single direction processing sequence is preferable due to better grain refinement, mainly in all regions of the processed samples. Gradual improvement was observed in microhardness with each additional pass, stronger refinement, and homogeneous grains in the processed regions (stir and overlapping zones). In the first pass’s stir zone (SZ), the microhardness is approximately 42.5 Hv, while it increases to an average of 43.4 Hv in SZ2 of the second pass and 44.3 Hv in SZ3 of the third pass. Furthermore, more resistance to plastic deformation (slip) and lower intensity of heat distribution when compared to the double direction. Therefore, the application of a single direction processing sequence can be beneficial in the welding of such aluminium alloys.

Microstructure, mechanical and tribological properties of AA5083-TiO2 nanocomposite by multi-pass friction stir processing

This study examines the impact of Friction Stir Processing (FSP) with TiO2 nanoparticle incorporation on the microstructural, mechanical, and tribological properties of AA5083 Metal Matrix Composites (MMCs). It offers a detailed analysis of the alterations in the alloy’s characteristics due to FSP. Microstructural examination was conducted using optical microscopy (OM) and scanning electron microscopy (SEM). Significant findings include the microstructural refinement where TiO2 nanoparticle addition during FSP shrank the grain size from 20 to 3 µm after one pass, which then rose to 7 µm following four passes. Mechanical properties, specifically microhardness and tensile strength, were assessed. Results indicated that after four FSP passes, the material can reach a yield strength of 192 MPa and an ultimate tensile strength (UTS) of 359 MPa, alongside a consistent microhardness of 103 HV0.1. Furthermore, it was observed that increasing FSP passes enhances energy absorption, although it remains lower than that of the base material. Analysis of fracture and wear mechanisms has led to the conclusion that with more passes, fracture mechanisms transition to a mix of ductile and brittle behaviors, and the friction coefficient decreases by up to 22.95%.

CoCrFeNiMoTi High-Entropy Alloy Reinforced Mg Matrix Composites Produced by Multi-pass Friction Stir Processing: Focus on Pin Geometry, Microstructure and Mechanical Properties

CoCrFeNiMoTi High-Entropy Alloy Reinforced Mg Matrix Composites Produced by Multi-pass Friction Stir Processing: Focus on Pin Geometry, Microstructure and Mechanical Properties

The study of the effects of grain size, orientation and dislocation density on the HER performance of copper catalysts

Utilizing multi-pass friction stir processing with recirculating water cooling, pure copper plates were processed to successfully synthesize catalysts with distinct grain sizes. An exhaustive investigation into their intrinsic structures and properties was conducted. Analyses using X-ray diffraction (XRD) and electron backscatter diffraction (EBSD) revealed that Cu-4.85 exhibits a preferred (111) crystallographic orientation along with a high dislocation density. Transmission electron microscopy (TEM) images clearly identified the types of dislocations present within Cu-4.85. Density functional theory (DFT) calculations further demonstrated that Cu-4.85 displays lower Gibbs free energy at the hollow site on the (111) plane, thereby facilitating the H* adsorption process. Collectively, this study delves into the cooperative influence of grain size, crystal orientation and dislocation density on the electrocatalytic hydrogen evolution (HER) performance. It was found that Cu-4.85 demonstrates exceptional HER activity, characterized by a reduced overpotential and a low Tafel slope. The study elucidates the mechanism of H atom adsorption in Cu-4.85 during the HER process, furnishing theoretical foundations for enhancing HER catalytic performance and offering significant theoretical and experimental insights for the design and fabrication of copper catalytic electrodes.

The Influence of Multi-Pass Friction Stir Processing on the Microstructure Evolution and Mechanical Properties of IS2062 Steel

The motive of present work is to explore the variation in the material characteristics of steel upon multi-pass friction stir processing. Steel plates (IS2062) that were 3 mm thick, were subjected to friction stir processing in a multi-pass manner. The selected transverse speed was 150 mm/min, along with a tool rotation of 800 RPM when using a tungsten carbide tool (shoulder diameter—10 mm). Steel plates were processed using the single-pass, double-pass, and triple-pass travel of the rotating tool to observe the impact of multi-pass processing on the properties of steel plates. Multi-pass friction stir processing resulted in a higher micro-hardness of 175 VHN after the second pass, in comparison to the unprocessed metal, which had a micro-hardness of 130 VHN, owing to the collective effect of the plastic flow of the material due to the rotation of the tool and frictional heat, which also leads to grain refinement. The second pass evidenced an average grain size of 22 microns, whereas the unprocessed material had an average grain size of 57 microns. The results of EBSD and SEM characterization showed reasonably improved material properties of the processed work materials.

Enrichment in Fracture Ductility Tribological Characteristics of Magnesium-Based Nanocomposites Fabricated via Multi-pass Friction Stir Processing and Study of Significant Parameters

Enrichment in Fracture Ductility Tribological Characteristics of Magnesium-Based Nanocomposites Fabricated via Multi-pass Friction Stir Processing and Study of Significant Parameters

Effect of multi-pass friction stir processing and rolling on microstructure of interface structure and mechanical properties of 2024Al/AZ31B composites

Al/Mg laminated composites were successfully prepared by multi-pass friction stir processing(M-FSP) and rolling, and the effects of interface structure on their microstructure and properties were studied by Scanning Electron Microscopy (SEM) and Backscattering Diffraction (BSD). The results showed that there were two layers of intermetallic compounds (IMCs) at the interface of the composites after M-FSP, and the average grain size on 2024Al and AZ31B layers decreased from the initial 12.79 μm and 15.06 μm–3.59 μm and 6.36 μm, respectively. For M-FSP + Rolling(F + R) samples, after rolling process, the initially straight IMCs layers were fragmented and embedded on the two matrix layers to increase the interface bonding, while the average grain size on the 2024Al and AZ31B sides were further refined to 2.16 μm and 4.26 μm. The ultimate tensile strength of the F + R sample was increased to 20.6%, with an average value of 322 MPa, compared with the M-FSP samples. This research using M-FSP + Rolling can improve the interface bonding and refine the microstructure, thereby improving the mechanical properties of the composites.

Toward Achieving Grain Refinement in Al2014 Alloy Through Multi-pass FSP: Microstructure and Mechanical Behavior

Toward Achieving Grain Refinement in Al2014 Alloy Through Multi-pass FSP: Microstructure and Mechanical Behavior

Surface CuAl9Mn2/W Composites Prepared by Multipass Friction Stir Processing: Microstructures, Phases, and Mechanical and Tribological Properties

Surface CuAl9Mn2/W Composites Prepared by Multipass Friction Stir Processing: Microstructures, Phases, and Mechanical and Tribological Properties

Microstructure, mechanical and tribological properties of Mg/CoCrFeNiMoTi high entropy alloy composites produced via FSP

In this study, multi-pass friction stir processing (FSP) was used to produce magnesium (Mg) matrix composites reinforced with CoCrFeNiMoTi high entropy alloy (HEA) particles. The effect of the HEA reinforcements on microstructure evaluation, mechanical properties (hardness and tensile) and wear performance was investigated. The composites were produced with similar pass number (three passes) and tool rotation speed (1250 rpm) and different tool transverse speeds (25 and 50 mm/min) and compared with the Mg matrix without reinforcing particles. XRD results indicated no significant reaction at the interface of the HEA and the matrix during FSP. Microstructure results showed the distribution improvement of the HEA reinforcements and elimination of lamellar structure (inhomogeneous structure) with the decrease of the tool transverse speed from 50 to 25 mm/min. Microstructures of all specimens illustrated four microstructural regions including stirring zone, thermo-mechanical affected zone, heat-affected zone and base metal. The average grain size of the stir zone reduced significantly from 12 µm for the Mg-50 to 2.5 µm and 1.6 µm for the Mg/HEAs-50 and Mg/HEAs-25 composites. The hardness value was increased from 34 HV for the base alloy to 113 HV for the FSPed composite at 25 mm/min (232 % improvement). The maximum yield and tensile strengths were obtained as 86.4 MPa and 114 MPa for the FSPed composite at 25 mm/min which presented enhancement of 92 % and 43 %, respectively as compared with the FSPed Mg alloy. The wear resistance results showed the reduction of the friction coefficient and wear rate with the addition of the HEA reinforcements with a considerable decrease in wear debris, groove depth, micro-cracks and delamination. Comparative plots confirmed that the hardening and strengthening effects of the HEA reinforcements were significantly higher than other reinforcements in Mg matrix composites.

Multi-response optimization of input and output responses of multipass FSP of AA7050 with (SiC + TiB2) nanoparticles by response surface methodology

In this work, multi-response optimization of output and input responses of multipass friction stir processing (MPFSP) of AA7050 with (SiC + TiB2) nanoparticles by response surface methodology based on the center composite design and metallurgical characterization were analyzed, and the optimum parameters of the MPFSP were discussed. At high tool rotational speed (TRS) of 1100 rpm with 50% TiB2 and 100% SiC nanoparticles, maximum joint efficiency (137.80%) was observed due to uniformly dispersed SiC and TiB2 within the matrix, serving as practical obstacles to dislocation motion, hindering plastic deformation, and facilitating enhanced mechanical properties. MPFS and nanoparticles broke the coarse grain structure of the base metal and produced a fine and homogenous grain structure in the stir zone. Increasing the concentration of reinforcement particles and FSP passes (1 to 4) inhibited grain boundary migration and significantly reduced the high-angle grain boundary and grain size. The optimized value of input parameters TRS, TiB2 nanoparticles, and SiC nanoparticles was observed as 1068 rpm, 56%, and 97%, while the optimized value of output response tensile strength, % strain, and hardness value was found as 569.16 MPa, 20.79, and 148.32 HV respectively. The p-value for all three models remained below 0.05, indicating a confidence level exceeding 95% in the constructed models, rendering them suitable for design exploration. The hardness value range of MPFSP/(SiC + TiB2) lies between 130 HV and 190 HV. The minimum hardness value of 131.03 HV was observed at 0% TiB2 and 50% SiC reinforcement particles with TRS of 1100 rpm, while the highest microhardness (187.02 HV) was perceived at 1000 rpm.

Al-5052/SiC + CeO2 hybrid surface composites: Achieving improved microstructural and mechanical behaviour via friction stir processing

In the present work, hybrid surface composites (HSCs) were fabricated using aluminium 5052 alloy as base matrix and silicon carbide (SiC) and cerium oxide (CeO2) as reinforcement particles via friction stir processing (FSP) technique. Varying reinforcement ratios of SiC and CeO2 nano-powders, viz 100:0, 75:25, 50:50, 25:75, and 0:100 was used. Multi-pass FSP was employed to obtain improved dispersion of reinforcement particles. Results revealed the collaborative impact of SiC and CeO2 particles on the mechanical properties of the SCs, shedding light on the optimal ratios for achieving superior mechanical performance. The hybrid ratio of (SiC: CeO2) 75:25 was predominant in tensile strength enhancements with an ultimate tensile strength of 283 MPa compared to 269 MPa of BM while the percentage elongation increased to 21.6 as compared to 18.8 in BM. The average microhardness also improved to 92 HV compared to 85 HV. These results emphasised on the importance of HSC fabricated using 75:25 ratio of SiC:CeO2 reinforcing particles.

A novel counter-rotating twin-tool friction stir processing technology for fabrication of Al/SiC surface composite with improved particle distribution

The fabrication of surface composite through friction stir processing (FSP) introduces certain challenges, including insufficient heat generation and non-uniform distribution of reinforcement particles. The implementation of multi-pass FSP can partially reduce these issues; however, it comes at the cost of increased manufacturing time and labour costs. In order to address these challenges comprehensively, a novel counter-rotating twin-tool friction stir processing (CRTTFSP) technology was utilized for fabrication of Al/SiC surface composite. The presence of hard SiC particles notably improved the microhardness of the composite. High heat generation and counter-rotation of the twin-tool, contributed to better particle distribution, which led to consistent microhardness values. Hence, this technology offers uniform mechanical properties of the fabricated composite and also eliminates the need of repetitive processing over the same zone, resulting in considerable reductions in both manufacturing time and associated costs making it more suitable for industrial applications.

Effect of multiple passes on the properties of Al-5052/SiC surface composites fabricated via friction stir processing

Friction stir processing (FSP) has emerged as a promising technique for producing surface composites with enhanced mechanical, microstructural and tribological properties. This work investigates the influence of multi-pass FSP on various properties of aluminium 5052 alloy reinforced with silicon carbide (Al-5052/SiC). The results indicated that multi-pass FSP effectively dispersed SiC particles within the aluminium matrix, resulting in a refined microstructure and improved mechanical properties. As the number of FSP passes increased, hardness, tensile strength, and wear resistance improved, reaching levels significantly higher than the base Al-5052 alloy. Tensile strength, yield strength, and average microhardness in the five-pass FSPed specimen were improved by about 25 %, 26 %, and 28 % respectively. Wear and corrosion resistance improved with the increase of FSP passes. The quantitative results of the study strongly corroborate with microstructural evolution.

Friction and wear analysis of Al-5052/NiTi surface composites fabricated via friction stir processing

This work presents a comprehensive analysis of the wear behaviour of Al 5052 alloy reinforced with Nitinol (NiTip) shape memory alloy using friction stir processing (FSP). Multi-pass FSP was performed to improve the dispersion of NiTip in the base material. The reinforced NiTip significantly enhanced the wear resistance of the base material and led to a reduction in the coefficient of friction by 17% and 15% at 15 N and 25 N loads respectively, suggesting improved tribological properties. The corrosion resistance also showed a significant improvement in the four-pass FSPed specimen as compared to the base metal. The qualitative analysis of the study is in agreement with the quantitative results.

Effects of friction stir processing and nano-hydroxyapatite on the microstructure, hardness, degradation rate and in-vitro bioactivity of WE43 alloy for biomedical applications

Nowadays, magnesium alloys are emerging in biomedical implants for their similar properties to natural bones. However, the rapid degradation of magnesium alloys in biological media hinders successful implantation. Refinement of microstructure, as well as reinforcement particles can significantly improve the degradation rate. In this work, multi-pass friction stir processing (FSP) was proposed to synthesize WE43/nano-hydroxyapatite (nHA) surface composite, the microstructure, reinforced particle distribution, micro-hardness, corrosion behavior and in-vitro bioactivity were studied. The subsequent FSP passes of WE43 alloy and WE43/nHA composite refined the grain size which was reduced by 94.29% and 95.92% (2.63 and 1.88 µm, respectively) compared to base metal after three passes. This resulted in increasing the microhardness by 120% (90.86 HV0.1) and 135% (105.59 HV0.1) for the WE43 and WE43-nHA, respectively. It is found that increasing FSP passes improved the uniform distribution of nHA particles within the composite matrix which led to improved corrosion resistance and less degradation rate. The corrosion rate of the FSPed WE43/nHA composite after three passes was reduced by 38.2% (4.13 mm/year) and the degradation rate was reduced by 69.7% (2.87 mm/y). This is attributed to secondary phase (Mg24Y5 and Mg41Nd5) particle fragmentation and redistribution, as well as a homogeneous distribution of nHA. Additionally, the growing Ca-P and Mg(OH)2 layer formed on the surface represented a protective layer that reduced the degradation rate. The wettability test revealed a relatively hydrophilic surface with water contact angle of 49.1 ± 2.2° compared to 71.2 ± 2.1° for base metal. Also, biomineralization test showed that apatite layer grew after immersion 7d in simulated body fluid with atomic ratio of Ca/P 1.60 approaching the stoichiometric ratio (1.67) indicating superior bioactivity of FSPed WE43/nHA composite after three passes. These results raise that the grain refinement by FSP and introduction of nHA particles significantly improved the degradation rate and in-vitro bioactivity of WE43 alloy for biomedical applications.

Effect of nanoparticles adhesion and multipass friction stir processing on metallurgical properties of AZ91D magnesium alloy

In this work, the effect of SiC and Al2O3 nanoparticles and multipass friction stir processing (MPFSP) on the metallurgical properties of AZ91D was carefully investigated and observed a homogenous dispersion of nanoparticles and refined grain size in the processed zone. The presence of the Mg17Al12 intermetallic compound in the MPFSP of AZ91D with SiC and Al2O3 nanoparticles has significant implications for the material’s properties. Mg17Al12 is a typical intermetallic phase formed in magnesium alloys and can profoundly affect thermal, microstructural, and mechanical properties. The intermetallic phase can improve the processed region’s strength due to its inherent hardness and solid solution strengthening effect, resulting in enhanced tensile properties and hardness. As the FSP passes increased, the tendency for reinforcement agglomeration diminished. Before undergoing MPFSP/(SiC + Al2O3), the base metal AZ91D exhibited an ultimate tensile strength (UTS) of 208.36 MPa and a strain percentage 15.72. After implementing MPFSP/(SiC and Al2O3) on AZ91D, the UTS consistently increased with each FSP pass. This effect was evident at the fourth FSP pass, yielding a higher UTS of 284.35 MPa. In essence, this process facilitated a marked enhancement in the metallurgical properties of AZ91D, signifying the efficacy of the MPFSP approach when combined with reinforcement particles. The hardness value was higher when the indenter engaged with Mg17Al12 than α-Mg. The SZ of 4-pass FSP (Al2O3+SiC)/AZ91D reached a maximum hardness value of 69.37 HV, while single-pass FSP (Al2O3)/AZ91D exhibited a minimum value of 64.89 HV.

Microstructure and tribological properties of as-cast and multi-pass friction stir processed Mg-0.5Zn-0.5Zr/SiC composite fabricated by stir casting technique

In this investigation, the Mg-0.5Zn-0.5Zr/4%SiC composite fabricated by the stir casting method was subjected to multi-pass friction stir processing (MFSP) to evaluate its microstructure, hardness, dry-sliding wear, and friction properties in comparison to those of the as-cast composite (ACC). Microstructural observations revealed the formation of a Mg matrix with average grain size (AGS) of 107 ± 12 μm, uneven dispersion (agglomeration) of SiC particles in the structure, and the formation of Zr-rich phase with the chemical composition of Zr:78.42, C:19.46, Mg:1.86, and Zn:0.26 wt%, ZrC, as well as some new formed carbide-based phases mostly propagated along the grain boundaries. On the other hand, the MFSP implementation led to a significant microstructural modification, i.e., in the optimum circumstance, the AGS and SiC particle size in the stir zone was reduced by 97.28 % (107–2.9 μm) and 67.69 % (21.33–6.89 μm), respectively, and the density of the composite increased from 1.669 to 1.774 gr/cm3. According to dry-sliding wear test results, applying FSP and increasing the pass number to three reduced the wear rate and coefficient of friction (COF) of the composites by about 45 % and 24 %, respectively, compared to those of ACC. The wear resistance enhancement was ascribed to wear mechanisms changing from delamination/adhesion/severe abrasion to mild abrasion wear, which stemmed from the formation of a stable O-rich tribolayer on the worn surface of FSPed samples.

Adopting continuous multi-pass friction stir processing to enhance the wire-arc additive manufactured ER2319 thin-walled part

Adopting continuous multi-pass friction stir processing to enhance the wire-arc additive manufactured ER2319 thin-walled part

Correction to: Modification of Microstructure and Mechanical Properties of AA6082/ZrB2 Processed by Multipass Friction Stir Processing

Correction to: Modification of Microstructure and Mechanical Properties of AA6082/ZrB2 Processed by Multipass Friction Stir Processing