MPa Ultimate Tensile Strength Research Articles

Suppressing formation of microcracks in laser powder bed fusion manufactured AA6061 aluminum alloy by introducing mechanical alloyed Al-25at%Ti particles

A novel approach which incorporates mechanical alloyed Al-25at%Ti particles into an AA6061 aluminum alloy powder feedstock has been used to suppress pronounced hot cracking that normally occurs in laser powder bed fusion (LPBF) manufactured AA6061 alloy. Investigation of the microstructure and tensile properties of the Ti-modified AA6061 sample fabricated by LPBF confirms the effectiveness of this approach. The suppression of microcrack formation is associated with the transition of a coarse columnar structure to fine equiaxed structure facilitated by heterogeneous nucleation of the grains on Al3Ti nanoparticles. This crack-free microstructure also results in excellent tensile properties of 252 MPa in yield strength, 361 MPa in ultimate tensile strength, and 9.7 % in elongation to fracture.

Controlling of cellular substructure and its effect on mechanical properties of FeCoCrNiMo0.2 high entropy alloy fabricated by selective laser melting

Fine cellular substructures are typical microstructure feature of high entropy alloys (HEAs) produced via selective laser melting (SLM), playing a pivotal role in improving the mechanical properties. Nonetheless, the controlling of cellular substructure and its impact on the mechanical properties remains ambiguous. This study investigates the effect of energy densities on the cellular substructure evolution and mechanical properties of the FeCoCrNiMo0.2 HEA. It is found the increase in energy density causes a decrease in temperature gradient (G) and solidification rate (R) in molten pool, consequently leading to the increase of cellular substructure size and the intensification of Mo segregation at cellular substructure boundaries. The cellular substructure size (d) can be described by formula d=80(GR)−1/3, in which G and R can be obtained from discrete element method - computational fluid dynamics (DEM-CFD) simulation. The strength of the FeCoCrNiMo0.2 HEA is significantly affected by dislocation strengthening (σd) and segregation strengthening (σs), which are further determined by the cellular substructure size and the Mo segregation, respectively. The increase of cellular substructure size leads to the decrease of σd, while the intensification of Mo segregation results in the increase of σs. The competition between these two strengthening effects leads to an optimized and excellent tensile property of 707 MPa in yield strength, 947 MPa in ultimate tensile strength and 34 % in fracture elongation at a moderate energy density of 47 J/mm3. The findings provide guidance towards the advancement of high-performance high entropy alloys fabricated by SLM in terms of cellular substructure controlling.

A high strength and high electrical conductivity copper based composite enhanced by graphene and Al2O3 nanoparticles

The rapid development of electrical and electronic engineering requires to further surmount the trade-off between the electrical conductivity and strength of Cu matrix composite. In this study, the surface of Cu–Al2O3 powder is selective for carbon sources, and only α-naphthol can prepare graphene. Graphene and Al2O3 particles are simultaneously incorporated into Cu matrix by hot-press sintering Cu–Al2O3 powders by internal oxidation coated with in-situ grown graphene. This composite exhibits a good combination of strength and conductivity (600 MPa of ultimate tensile strength and 81.7 % IACS of electrical conductivity) due to synergistic effect of graphene and Al2O3 particles. This composite fabricated by such synergistic more effectively retains the microstructure induced by plastic deformation during the cold-rolling process. Both graphene and Al2O3 particles uniformly distribute in Cu matrix. Coherent Al2O3 particles and graphene in situ grown can be well enhance to Orowan looping mechanism effect, and the addition of graphene in Cu matrix composite with Al2O3 particles can improve dislocation strengthening and dispersion strengthening at the same time. Our study provides an effective route to achieve simultaneously high strength and conductivity of Cu matrix composites.

Improving ductility in dual-phase FeNi2Al medium-entropy alloy through rapid solidification-induced expansion of Interface transition zones

Multi-principal element alloys (MPEAs), renowned for their exceptional properties, have garnered significant attention in materials science. However, their limited ductility has restricted their widespread applications. In our investigation, the toughness of a Co-free dual-phase (B2 + L12) FeNi2Al medium-entropy alloy was improved by manipulating the microstructure through rapid solidification. A significant improvement in the total tensile elongation (TE) and ultimate tensile strength (UTS) of the as-cast FeNi2Al alloy at 253 K compared to the as-melted counterpart can be observed. Specifically, the as-cast alloy exhibited enhanced values of 13.1% for TE and 1111.0 MPa for UTS, whereas the as-melted FeNi2Al alloy displayed 6.1% for TE and 1176.2 MPa for UTS. This represents a remarkable 114.1% increase in TE, with only a marginal 6.3% decrease in UTS. Microstructure analysis indicates that augmenting the L12 phase content, refining the grain size, and fostering interfacial transition zones between the B2 and L12 phases, all achieved through rapid solidification, collectively contributed to the improved ductility of the FeNi2Al alloy. This work presents an effective and promising strategy for enhancing the ductility of multi-phase MPEAs, offering new opportunities for their broader application in various industries.

Multi-scale microstructure manipulation of an additively manufactured CoCrNi medium entropy alloy for superior mechanical properties and tunable mechanical anisotropy

Laser beam powder bed fusion (PBF-LB) additive manufacturing (AM) technology has become a versatile tool for producing new microstructures in metal components, offering novel mechanical properties for different applications. In this work, enhanced ductility (∼55% elongation) and tunable mechanical anisotropy (ratio of ductility along vertical to horizontal orientation from ∼0.2 to ∼1) were achieved for a CoCrNi medium entropy alloy (MEA) by multi-scale synergistic microstructure manipulation (i.e., melt pool boundary, grain morphology and crystallographic texture) through adjusting key PBF-LB processing parameters (e.g., laser power and scan speed). By increasing the volumetric energy density (VED) from 68.3 to 144 J/mm3, the melt pool size enlarges, and the crystallographic texture transitions from <100>//BD to <110>//BD due to the maximum thermal flux direction changing for different melt pool dimensions, which affects the proportion of grains that have different growth directions. Moreover, excellent mechanical properties of 890 MPa ultimate tensile strength and ∼55% elongation to failure can be achieved for loading perpendicular to the build direction with only a ∼15% reduction in properties for loading along the build direction. The superior combination of mechanical properties is achieved by processing parameter-controlled strengthening of melt pool boundary interfaces, heterogeneous deformation induced strengthening through bimodal grain structures, and favorable grain orientation for dislocation slip and twinning formation, which was significantly more activated in the <110>//BD texture than in the <100>//BD. This study offers new insights into achieving multi-scale synergistic microstructure manipulation via PBF-LB for desired strength, ductility, and mechanical anisotropy in a CoCrNi MEA.

Metastable microstructure evolution and grain refinement in a Low-Ta containing γ-TiAl alloy through heat treatment

The paper comprehensively describes the evolution of metastable microstructures in a cast low-Ta-containing γ-TiAl alloy during cooling-tempering-lamellarization heat treatments. The behavior and mechanism of microstructure refinement are discussed. The rapid cooling generates metastable microstructures, including Widmanstätten, feathery, and massive structures, with many γ variants in small sizes and different orientations. It significantly refines the coarsened colonies and randomizes the texture. The tempering can effectively stabilize the metastable microstructures. During tempering, the γ→α phase transformation is more active at higher temperatures while coarsening and recrystallization dominate at lower temperatures. After tempering, a refined microstructure with spherical grains and convoluted structures forms. Subsequent lamellarization treatment optimizes the microstructure and obtains a fine-grained nearly-lamellar microstructure with small colonies (∼70 μm) and dispersed fine γ grains (∼10 vol%), which yielded a 1.0 % elongation with a 487 MPa yield strength (0.2%) and a 589 MPa ultimate tensile strength at room temperature. Finally, the unique promotion effects and mechanism of a small amount of Ta addition on the nucleation, growth, evolution, and stabilization of metastable microstructures are concluded and discussed, which is crucial for the refinement of cast γ-TiAl alloy by heat treatment alone.

Enhanced Yield Strength and Total Elongation of an Ultrahigh Strength Hot‐Stamped Steel via Tempering Treatment

A 2460 MPa ultimate tensile strength (UTS) has been achieved in this experimental steel, which was processed by a conventional hot stamping process with water quenching to room temperature. Additionally, comparing the microstructure evolution and strengthening mechanism before and after tempering, the microstructure has changed from fresh martensite transformed into tempered martensite with acicular carbides, and the fracture mode has also changed from brittle fracture transformed into ductile fracture mainly. Meanwhile, the main strengthening mechanism has changed from dislocation strengthening to precipitation and dislocation strengthening. Overall, the tempering process reduces dislocation density and produces acicular carbides, which decrease UTS. However, the tempering process reduces the quenching residual stress and changes the morphology of twin martensite, resulting in an increase in ductility. Meanwhile, it enhances the effect of carbide pinning dislocations, significantly enhances precipitation strengthening, and improves yield strength.

Temperature dependence of mechanical strength in HPDC Mg–6Y–3Zn–1Al alloy with LPSO phase

The temperature dependence of mechanical strength including yield strength (YS) and ultimate tensile strength (UTS) in HPDC WZA631 alloy is investigated in a wide temperature range from room temperature (RT) to 350 °C. It is found that at 25–300 °C, YS and UTS do not drop markedly, from 173 MPa and 274 MPa at RT to 113 MPa and 170 MPa at 300 °C, respectively. While above 300 °C the flow stress falls rather rapidly, to 74 MPa for YS and to 108 MPa UTS at 350 °C. The (Al,Zn)2Y phase exhibits similar behavior between 150 °C and 350 °C, breaking up under stress and becoming the relatively stable crack source without catastrophic cracking. The LPSO phase, keeping steady and excellent critical resolved shear stress (CRSS) below 250 °C, remains unchanged with complete network structure at 150 °C and 250 °C. Therefore, the LPSO phase reinforces the alloy with slow flow stress reduction at RT-300 °C for WZA631 alloy. The tensile property deteriorates above 300 °C due to the destruction of the network structure as well as the reduction of CRSS for the prismatic slip of LPSO under tensile loading. Thus, the LPSO phase determines the mechanical strength evolution of WZA631 alloy, which is similar to the behavior of γ’ phase in the Ni-based superalloys. Besides, the relationship between strength and temperature is described by the Arrhenius equation, which may be reduced to an exponential model in the form of σ=a+bT for HPDC WZA631 alloy.

Study on microstructure evolution and mechanical properties of similar joint of Al-Mg-Si alloy by tungsten inert gas welding

Study on microstructure evolution and mechanical properties of similar joint of Al-Mg-Si alloy by tungsten inert gas welding

Thermo-mechanical properties of ABS/stainless steel composite using FDM

Fused deposition modelling (FDM) process is the most common and traditional additive manufacturing methods for producing complicated three-dimensional (3D) samples from computer-aided design data at a cheaper cost than alternative methods. However, when compared to other common plastic production processes, such as injection moulding, FDM produced parts results in low mechanical properties. Hence, the objective of this study is to produce composite filament using stainless steel (SS) as filler material to enhance the mechanical properties of ABS. ABS is a petroleum based thermoplastic that commonly used in FDM. The production of metal/polymer composites utilising ABS as the matrix and varied SS powder compositions was studied in this work. ABS/SS composite filaments containing 5, 10 wt% SS powder were developed in this experiment to compare with pure ABS for the FDM process. The result shows that the higher the composition of SS powder the lower the ultimate tensile strength and yield strength where 10 wt% SS shows 38.42 MPa in ultimate tensile strength while for yield strength it shows 24.32 MPa. Meanwhile, 10 wt% SS filament has better elongation which is 18.28 % compare to pure ABS that is 9.89 % and 13.3 % for 5 wt% SS. Thus, the percentage of filler plays an important role in determining the properties of ABS.

Development of a Tri-Layered Vascular Construct and In Vitro Evaluation of Endothelization.

Advances in the development of vascular substitutes for small-sized arteries are ongoing because the present grafts do not entirely meet the requirements of native equivalents and are suboptimal in clinical performance. This study aims to develop a tri-layered vascular construct mimicking natural tissue using polyester blends and to investigate its endothelization through in vitro studies as a potential small-caliber vascular graft. The innermost layer is obtained by dip coating as a tubular porous film with a lumen diameter of 3mm and a pore size of ≤8µm. Circumferentially aligned electrospun fiber (diameter 100-800nm) with a deviation angle of 15° are deposited over the porous film forming the intermediate layer. The random electrospun fibers (diameter 100-1100nm) deviating at different angles are wrapped as the outermost layer. The mechanical properties of the tri-layered vascular construct are determined to be 44.80±14.80MPa for Young's modulus and 4.25±0.75MPa for ultimate tensile strength. MTS and cell behavior studies show that the isolated human umbilical cord vein endothelial cells proliferate and line the lumen of the vascular substitute. The vascular construct developed, with its biomimetic architecture, mechanical features, size, and endothelization, can be tested with in vivo studies.

Experimental investigations on microstructure and mechanical properties of wall structure of SS309L using wire-arc additive manufacturing

In present study, a wall structure of SS309L was constructed through Gas metal arc welding based Wire-arc additive manufacturing process. The wall structure of SS309L underwent investigation for microstructure and mechanical properties at three positions along the horizontal deposition direction. Mechanical assessments, including microhardness testing, impact testing, tensile testing, and fractography, were conducted at three positions of walls. Microstructure study has shown a fine granular structure in addition to colony of columnar dendrites in bottom section, a columnar dendrites in middle section, and a mix of dendritic structure with even coarser structures in top section. The mean microhardness values were observed to be 159 ± 4.21 HV, 162 ± 3.89 HV, and 168 ± 5.34 HV for the top, middle, and bottom sections, respectively. Results of impact testing for the wall structure indicated greater strength compared to wrought SS309L. The tensile strength of the built structure showed average values of yield strength, ultimate tensile strength, and elongation to be 409.33 ± 7.66 MPa, 556.66 ± 6.33 MPa, and 39.66 ± 2.33 %, respectively. In comparison, wrought 309 L steel typically exhibits tensile strengths in the range of 360–480 MPa for yield strength, 530–650 MPa for ultimate tensile strength, and 35–45 % elongation. Thus, the obtained tensile strength results for the wall structure fall within the range of tensile strength observed in wrought 309 L steel. Fractography of the tensile and impact specimens, as obtained through Scanning Electron Microscopy, revealed the superior ductility of the fabricated component. This study contributes valuable insights into the manufacturing of wall structure and their analysis regarding mechanical characteristics.

Structure-property relationships of differently heat-treated binder jet printed Co-Cr-Mo biomaterial

This investigation systematically examines the influence of sintering temperature and aging treatment on the density, microstructure evolution, phase formation, and mechanical properties of a binder jet printed Co-Cr-Mo biomedical alloy. Sintering at 1380 °C for 2 h yielded a near-fully dense part (99.1%) with favorable mechanical properties (up to 325 HV0.1 hardness and up to 693 MPa ultimate tensile strength). The grain size remained unchanged after aging at 800 °C for 24 h (89 ± 21 µm). Aging resulted in increased microhardness and tensile strength due to phase formation (Cr23C6, CrMo, and ε phase), but a significant decrease in ductility. Consequently, the sintered and aged specimen exhibited higher hardness (522 HV0.1), yield strength (641 MPa), and ultimate tensile strength (854 MPa) compared to cast Co-Cr-Mo alloy. Biocompatibility testing with fibroblasts showed a cell viability of 95 ± 2%, indicating that binder jet printing did not affect the biocompatibility of the Co-Cr-Mo alloy. Exemplary printed parts including hip-joint, partial denture, and small-scale knee joint were successfully demonstrated. This study highlights the comparable properties of binder jet Co-Cr-Mo alloy to the cast alloy, affirming its potential for biomedical applications.

Mechanical properties, corrosion behavior, and cytotoxicity of biodegradable Zn/Mg multilayered composites prepared by accumulative roll bonding process

Zinc (Zn), magnesium (Mg), and their respective alloys have attracted great attention as biodegradable bone-implant materials due to their excellent biocompatibility and biodegradability. However, the poor mechanical strength of Zn alloys and the rapid degradation rate of Mg alloys limit their clinical application. The manufacture of Zn and Mg bimetals may be a promising way to improve their mechanical and degradation properties. Here we report on Zn/Mg multilayered composites prepared via an accumulative roll bonding (ARB) process. With an increase in the number of ARB cycles, the thicknesses of the Zn layer and the Mg layer were reduced, while a large number of heterogeneous interfaces were introduced into the Zn/Mg multilayered composites. The composite samples after 14 ARB cycles showed the highest yield strength of 411±3 MPa and highest ultimate tensile strength of 501±3 MPa among all the ARB processed samples, significantly higher than those of the Zn/Zn and Mg/Mg multilayered samples. The Zn and Mg layers remained continuous in the Zn/Mg composite samples after annealing at 150 °C for 10 min, resulting in a decrease in yield strength from 411±3 MPa to 349±3 MPa but an increase in elongation from 8±1% to 28±1%. The degradation rate of the Zn/Mg multilayered composite samples in Hanks’ solution was ranged from 127±18 µm/y to 6±1 µm/y. The Zn/Mg multilayered composites showed over 100% cell viability with their 25% and 12.5% extracts in relation to MG-63 cells after culturing for 3 d, indicating excellent cytocompatibility. Statement of significanceThis work reports a biodegradable Zn/Mg multilayered composite prepared by accumulative roll bonding (ARB) process. The yield and ultimate tensile strength of the Zn/Mg multilayered composites were improved due to grain refinement and the introduction of a large number of heterogeneous interfaces. The composite samples after 14 ARB cycles showed the highest yield strength of 411±3 MPa and highest ultimate tensile strength of 501±3 MPa among all the ARB processed samples. The degradation rate of the Zn/Mg multilayered composite meets the required degradation rate for biodegradable bone-implant materials. The results demonstrated that it is a very promising approach to improve the strength and biocompatibility of biodegradable Zn-based alloys.

Effect of alloying element Zr on microstructure and properties of Cu−Y2O3 composites

Cu−Y2O3 and Cu−Y2O3−Zr composites were prepared via mechanical alloying and spark plasma sintering, and their microstructure and properties were systematically studied by using optical metalloscope, scanning electron microscope, transmission electron microscope, conductivity and tensile tests. It is found that the microstructure of the composites greatly affects mechanical behavior and electrical conductivity. The improvement of electrical property can be attributed to the formation of coherent Y4Zr3O12 particles and the preferential nucleation of Cu4Zr phase, which improves the interface between Y2O3 and Cu matrix, and reduces the dislocation density, respectively. In addition, the Cu−Y2O3−Zr composites can achieve 265.6 MPa of yield strength, 301.0 MPa of ultimate tensile strength, 23.6% of elongation, and 92.0%(IACS) of electrical conductivity.

Microstructure and mechanical performance of low-cost biomedical-grade Titanium-316L alloy

A 316L stainless steel (SS) alloy was developed with 1, 3, and 5 vol% titanium (Ti) reinforcement using the powder injection molding route, representing a low-cost option for biomedical implants. The investigation encompassed 1300 °C, 1350 °C, and 1380 °C sintering temperatures to ascertain the optimal physical and mechanical properties. Both sintering temperature and Ti influenced sintered density, and Ti mitigated the deleterious effects of residual carbon. At higher sintering temperatures, carbon and silicon tended to migrate and accumulate at the brink of Ti, leading to the formation of intermetallic compounds and increased brittleness. Dispersed Ti particles within the 316L matrix acted as nucleation sites and enhanced solid solubility with improved density. An astounding 96.11 % sintered density was achieved at 3 vol% Ti sample sintered at 1380 °C. During the tensile test, 5 vol% Ti at 1380 °C exhibited a low modulus of 58.9 GPa, which is highly desirable for orthopedic implant application. The XRD, SEM, tensile test, and nano-indentation results collectively provide evidence of beta-titanium formation during the sintering process. Conversely, the sample incorporating 3 vol% titanium, sintered at 1380 °C, demonstrated a balanced performance, showcasing 432.94 ± 12.8 MPa ultimate tensile strength, 3.06 ± 0.17 % elongation, 74.2 GPa modulus, and 322 MPa and 423 MPa 0.2 % offset flexural and compressive yield strengths, respectively. Notably, an improvised wear resistance test underscored its aptitude for sliding wear resistance, solidifying its potential as a promising candidate for biomedical implants.

Influence of Al and Ca on the Ductility of Mg–Al–Ca Alloys

Magnesium and its alloys offer huge potential for lightweight applications. However, many Mg alloys suffer from limited room‐temperature formability. It has previously been shown that the addition of aluminium and calcium to Mg can improve ductility. Therefore, in the present work, it is aimed to systematically vary the alloying content of Al and Ca and to study their effects on the slip system activity and crystallographic texture after rolling and recrystallization. In the results, it is shown that all investigated ternary alloys in the range of 1–2 wt% Al and 0.005–0.5 wt% Ca have an increased ductility (in the range of 10–17% increase compared to pure Mg), whereas the binary Mg–Al and Mg–Ca alloys suffer from limited ductility (10% tensile elongation) and strength (175 MPa ultimate tensile strength). Non‐basal and especially &lt;c + a&gt;‐slip is active in all compositions (in 15–33% of the grains examined). Basal‐type textures are observed for all compositions, but with significantly weaker basal peak intensities for Ca‐containing samples when compared to pure Mg. The combination of activation of the &lt;c + a&gt; slip system and texture weakening is discussed as being responsible for the improved ductility of the ternary Mg–Al–Ca alloys.

Ti386/TC4 clad plate manufactured by hot rolling and solution-aging treatment

Clad plate of high strength Ti386 and high plasticity TC4 is manufactured by hot rolling and solution-aging treatment. The interfacial microstructure and tensile properties of Ti386/TC4 clad plate are analyzed under different conditions. Results indicate that the clad plate subjected to 40% rolling reduction achieves a metallurgical bonding as there are no voids at Ti386/TC4 interface and the interfacial bonding strength is superior to the ultimate tensile strength (UTS) of Ti386 base (883 MPa). The microstructure of the clad plate is further refined as the rolling reduction increases to 80%, and the UTS of Ti386 increases to 921 MPa, which is still inferior to that the interface and TC4 base. After solution-aging treatment, the UTS of Ti386 is greatly improved to 1547 MPa, and the clad plate fractures at TC4 side with the UTS of 1010 MPa and elongation (δ) of 14.68%. Finally, the clad plate consisting of Ti386 with 1547 MPa UTS and TC4 with 14.68% δ is obtained with metallurgical interface.

INFLUENCE OF MECHANICAL AND THE CORROSION CHARACTERISTICS ON THE SURFACE OF MAGNESIUM HYBRID NANOCOMPOSITES REINFORCED WITH HAP AND RGO AS BIODEGRADABLE IMPLANTS

Magnesium composites stay relevant for the applications of biodegradable implant as they are harmless and possess characteristics such as density and elastic modulus analogous to the cortical bone in humans. But corrosion is one major issue associated with magnesium when the biomedical applications are contemplated. Moreover, load bearing abilities are also required in case of an orthopedic implant. In this study, to achieve the desired implant characteristics, hybrid nanocomposites (HNCs) of Mg–2.5Zn binary alloys such as metal matrix, hydroxyapatite (HAp), and reduced graphene oxide (rGO) as reinforcements were fabricated via the vacuum-assisted stir casting method. The overall weight percentage of the reinforcements was fixed at 3% and both the reinforcements varied in compositions by weight to prepare the samples S0 (Pure Magnesium), S1 (Mg–2.5Zn–0.5HAp–2.5rGO), S2 (Mg–2.5Zn–1.0HAp–2.0rGO), S3 (Mg–2.5Zn–1.5HAp–1.5rGO), S4 (Mg–2.5Zn–2.0HAp–1.0rGO), and S5 (Mg–2.5Zn–2.5HAp–0.5rGO), respectively. The influence of mechanical characteristics such as tensile strength, compressive strength, and microhardness as well as the corrosion over the surface of the nanocomposite in simulated body fluid (SBF) have been assessed for their suitability as biodegradable orthopedic implants. Results suggest that the fabricated nanocomposites exhibit superior characteristics in comparison to pure magnesium. Increasing the HAp from 0.5 wt.% to 2.5 wt.% enhanced the compressive strength and reduced the corrosion rate. On the other hand, increasing the rGO from 0.5 wt.% to 1.5 wt.% increased the tensile strength. The formation of apatite layer over the composites is observed in the SBF solution. Among all the fabricated hybrid nanocomposite samples, the sample S3 (Mg–2.5Zn–1.5HAp–1.5rGO) with equal wt.% of HAp and rGO exhibited 209.60 MPa of ultimate tensile strength, 300.1 MPa of ultimate compressive strength, and a corrosion rate of 0.91 mm/year thus making it the best suited and a prospective material for biodegradable implant application.

Influence of tool pin profile on the mechanical strength and surface roughness of AA6061-T6 overlap joint friction stir welding

This study presents the tensile strength and surface roughness resulting from friction stir welding (FSW) on the lap joint method using AA 6061 –T6. FSW is conducted by comparing three different tool pin shapes: hexagon, thread, and square. Overlap welding using the FSW method is challenging if machine parameters, such as spindle speed and feed rate, are incompatible. The experiment was conducted using a conventional milling machine with a spindle speed of 1400 -1750 rpm and a feed rate of 20 – 30 mm/min. The results show that a spindle speed of 1750 rpm and a feed rate of 30 mm/min using a square tool pin results in 83.5088 MPa ultimate tensile strength and 0.85 µm surface roughness (Ra), which is much better than hexagon and thread type tool pins. In addition, the overall results on all three tool pin shapes show that higher processing parameters increase tensile strength and surface roughness. This study revealed the effect of parameters on AA6061 –T6 and the resulting implications of mechanical strength and surface roughness.