Multi-pass Friction Stir Processing Research Articles

Fabrication of high-performance biomedical rare-earth magnesium alloy-based WE43/hydroxyapatite composites through multi-pass friction stir processing

Magnesium-based composites with bioactive ceramic particles addition are promising materials for biomedical implant applications. Nevertheless, the agglomeration of bioactive ceramic particles remains a challenge for fabricating high-performance biomedical magnesium-based composites. Herein, a novel high-performance biomedical rare-earth magnesium alloy-based WE43/hydroxyapatite (HA) composite is successfully fabricated via multi-pass friction stir processing (MP-FSP). Systematic investigations reveal that MP-FSP leads to a uniform distribution of HA particles and efficient elimination of defects. The microstructural analysis shows a significant grain refinement in the WE43 alloy from 49.4 μm to 2.4 μm under triple-passes FSP. The mechanical properties of the composite are enhanced significantly under triple-passes FSP, with yield strength, ultimate tensile strength, and elongation reaching 236.2 MPa, 278.6 MPa, and 14.2% respectively. Corrosion resistance is also improved, with a 30% reduction in the corrosion rate in SBF solution compared to the unprocessed alloy. Moreover, the MP-FSP fabricated composites exhibit superior corrosion-wear resistance, characterized by slight abrasive wear compared to the abrasive wear and severe pitting corrosion observed in the base WE43 alloy. These improvements are attributed to the synergistic effects of grain refinement, dispersion strengthening, enhanced interfacial bonding, and texture modification. Overall, these findings provide significant quantitative insights into the advanced fabrication techniques of magnesium-based composites for biomedical implant applications, highlighting the effectiveness of MP-FSP in enhancing both mechanical and corrosion-related properties.

Evaluation the effect of multi-pass friction stir processing on the wear, mechanical properties, and microstructure of the AA1050/ZrO2 surface nanocomposite

This work presents surface nanocomposites of aluminum alloy AA1050, reinforced with zirconium oxide (ZrO2) nanoparticles developed through multipass friction stir processing (FSP). This article attempts to study the effects of the number of passes on the wear rate, microhardness profile, tensile properties, and macrostructure of surface nanocomposites. The results demonstrate that an improved distribution of ZrO2 nanoparticles is obtained following each FSP pass, and that the number of passes increases with a decrease in stir zone (SZ) grain size. Consequently, it was found that applying FSP passes continuously enhances the materials' microhardness and tensile characteristics. In the microstructure development of the stir zone during the ZrO2 nanoparticle FSP, dynamic recrystallization (DRX) was an essential mechanism. The main reason for this is that surface nanocomposites with homogenous ZrO2 particle dispersion and no discernible particle clustering in the stir zone were shown by microstructural studies conducted through FSP, which significantly reduced the matrix grain size. The AA1050 base metal (BM) has an ultimate tensile strength, yield strength, and hardness of 59.2 MPa, 24 MPa, and 30.1 respectively. The nanocomposite generated by 5 FSP passes exhibits improved yield stress (55 MPa), tensile strength (94.5 MPa), and microhardness (86.5 HV), but its tensile ductility decreased from 34% to 23.8% when compared to the base metal. Tensile strength that is higher is the outcome of fine dimples' ability to pin the dislocation movement during tensile loading. According to fractographic studies, the ductile–brittle mode replaced the dimple-shaped ductile fracture mode.

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 42.5Hv, while it increases to an average of 43.4Hv in SZ2 of the second pass and 44.3Hv 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 evolution and grain refinement in 2319 aluminium alloy via wire arc additive manufacturing coupled with multi-pass friction stir processing

The present study investigates the alterations in 2319 aluminium alloy microstructure and properties induced by the WAAM-FSP process, including grain size, microhardness and tensile strength. The effects of multiple stirring friction processing and remelting on the grains were systematically investigated. The results demonstrated that the grains within the stirring zone underwent enlargement due to thermal remelting, while the size of the stirring zone decreased. Furthermore, multiple thermo-mechanical factors significantly intensified grain growth in the bottom of the stirring zone, resulting in an increase of up to 3.4 μm.Upon a second remelting process conducted on the top of the sample, the grain size in the stirring zone can reach 3.7 μm. Additionally, the bottom stirring zone exhibited a higher prevalence of deformed grains (21.7 %) of deformed grains caused by the extrusion during multiple stirring friction processing. The top region was subjected to less thermo-mechanical influence, resulting in a smaller grain size and an ultimate tensile strength of 192.6 MPa and a hardness of 90 HV0.2. This finding demonstrates highlights the impact of thermomechanical cycling on the grains within the multilayer samples prepared by the WAAM-FSP technique.

Enhancing microstructural integrity and mechanical performance of thick wire-arc directed energy deposited eutectic aluminum-silicon solid structure through continuous multi-pass friction stir processing

In wire-arc directed energy deposition (waDED), fabricating larger 3D components with single-layer tracks is challenging due to limitations in track thickness, requiring the development of bead overlapping strategies. However, fusion-based 3D-printed aluminum structures often show porosity and coarse-grained microstructures, limiting their industrial applications. To address these limitations, this study employs continuous multi-pass friction stir processing (FSP) on a waDED-produced aluminum block (140 mm × 150 mm × 28 mm). The severe plastic deformation induced by FSP triggers dynamic recrystallization (DRX), promoting the formation of equiaxed grains with an average grain size 8.75 times smaller than the as-fabricated waDED sample (67.03 μm vs 7.66 μm). Transmission Electron Microscopy (TEM) revealed decreased dislocation loops post-FSP, indicating DRX and dislocation annihilation. X-ray micro-computed tomography (X-CT) examination showed complete elimination of porosity in the waDED sample, owing to the intense mechanical stirring induced during FSP. Scanning electron microscopy (SEM) images of the waDED samples showed fibrous eutectic networks disrupted by FSP, leading to a uniform distribution of broken Si particles within the α-Al matrix. Hardness decreased by approximately 38 % (86 HV0.1 vs 53 HV0.1), while the average ultimate tensile strength decreased by about 4 % in the FSP-treated samples (159.19 MPa vs 153.02 MPa). Additionally, the formation of alpha fiber and weak cube texture components during FSP enhances ductility, as evidenced by a sixfold improvement in elongation (1.93 % vs 11.59 %). This textural transformation contributes to the characteristic deeper and more uniform dimples in the FSP-treated samples, indicative of ductile fracture, compared to the premature failure patterns in as-deposited samples.

Microstructural homogenization and mechanical enhancement of aluminum matrix composites via multi-pass friction stir processing with SiC reinforcements

In this study, the environmentally friendly friction stir processing (FSP) method was utilized to fabricate surface composites employing technical aluminum matrix 1050-H14 and aluminum alloy 6060-T4 reinforced with silicon carbide (SiC) particles. Microstructure analysis, employing light and scanning electron microscopy, in conjunction with comprehensive evaluations of hardness, compressive strength, and tribological properties, was conducted to elucidate significant findings. The results reveal that an augmented number of FSP passes contributes to the homogenization of microstructure, leading to the alteration of SiC particle morphology and fragmentation. Consequently, this phenomenon results in improved mechanical properties, particularly noteworthy in the case of AA6060-T4 alloy matrix composites, and enhanced wear resistance. Both AA1050-SiC and AA6060-SiC composites demonstrate notable increases in compressive strength compared to their unreinforced matrices. Particularly noteworthy is the substantial enhancement in compressive strength observed in the AA6060-SiCp composite, escalating from 249 to 331 MPa (at ε = 0.1) and from 398 to 715 MPa (at ε = 0.2) with an increase in the number of FSP passes. Additionally, FSP’s ability to precisely control process parameters such as tool rotational speed and traverse speed allows for the optimization of mechanical properties and microstructural characteristics tailored to specific application requirements. This study highlights the potential of FSP in fabricating high-performance aluminum matrix composites with superior strength and wear resistance, positioning it as a viable technique for advanced engineering applications. The environmentally friendly nature of FSP, due to its solid-state operation and reduced energy consumption, further underscores its suitability for sustainable manufacturing practices.

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.

Use of Multi-pass FSP treatment for improving mechanical properties and corrosion resistance of Mg-2Zn-HA composite

Magnesium (Mg) alloys are very popular among the biomaterials for biodegradable bone implants due to their suitable properties matching with that of human cortical bone. However, their poor corrosion resistance in biological fluid is a major constraint to become an ideal choice for bioimplants. The corrosion resistance of Mg-alloys is further retarded with microstructural impurities such as micro-pores, micro cracks, heterogeneous distribution of alloying element etc., which is commonly present in as-cast Mg-alloys. In present study, Friction stir processing (FSP) has been performed on Mg-2Zn alloy to refine the microstructures as well as to develop Mg-Zn-HA composites by using HA powder reinforcement. HA powder reinforcement was added using micro-grooves and multiple FSP passes on as-cast Mg-2Zn alloy having average grain size of 63.86 µm. Filling HA powder in 2-grooves and using 3-pass FSP, a refined microstructure having an average grain size of 7.15 µm and homogeneous distribution of HA powder was obtained for the developed Mg-Zn-HA composite. The Mg-Zn-HA composite developed with 3-pass FSP treatment has shown significant improvement in tensile strength and corrosion resistance as compared with as-cast Mg-alloy.

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.