High Creep Resistance Research Articles

Advanced Additive Manufacturing of Y2O3-Enhanced Dispersion Strengthened Steel

Oxide dispersion strengthened (ODS) alloys represent a cutting-edge solution for high-temperature applications, with enhanced mechanical properties achieved through the fine dispersion of oxide particles in a metallic matrix. These alloys are critical in industries such as gas turbines and nuclear reactors, where materials must withstand high temperatures and have high strength and creep resistance. Yttria oxide (Y2O3) is particularly effective in distributing nano-scale oxide particles, significantly enhancing the material’s thermal stability, oxidation resistance, and overall strength. Additive manufacturing (AM) technologies, such as selective laser melting (SLM), offer a novel route to streamline ODS steel production, allowing for efficient, complex component fabrication with improved control over material properties. This paper explores the role of Y2O3 in strengthening ODS steel and highlights the potential of AM techniques to revolutionize ODS manufacturing. A case study on the fabrication of 316L stainless steel with varying Y2O3 content using SLM is also reviewed, emphasizing the benefits and challenges of integrating Y2O3 in the AM process.

Impression creep behavior of extruded Mg–TiO2 composites prepared by powder metallurgy

Magnesium (Mg) composites with ceramic fillers are considered favorable for their recyclability compared to Mg alloys for lightweight designs with high creep resistance. In this work, we studied the difference in impression creep properties of pure magnesium and its composites, which contained 2, 3.5, and 5 vol% of submicron TiO2 particles. For each composition, samples were fabricated by hot extrusion after hot pressing of the cold-compacted powders. Creep tests were conducted at temperatures in the 423–473 K range and under stress levels in the 125–275 MPa range. The results showed that the composites had higher creep resistance than pure magnesium, and increasing TiO2 content improved their creep behavior under all testing conditions. The effect of TiO2 content on grain size was statistically insignificant, and therefore, the improvement was attributed to reinforcing ceramic particles, which reduce the creep load on the magnesium matrix. The Dorn model was used in a new approach to calculate the effective stress on the magnesium matrix, justifying composites' higher creep load-bearing capacity than pure Mg under studied creep conditions. Fitting the Dorn exponential equation to creep data revealed that the stress exponent was between 6.6 and 8.6, and the activation energy was between 90.1 and 95.2 kJ/mol for all compositions. Therefore, it was inferred that pipe diffusion-controlled dislocation climb was the creep mechanism for the studied materials.

Exploiting Lignin Structure and Reactivity to Design Vitrimers with Controlled Ratio of Dynamic to Non-Dynamic Bonds.

Lignin is an abundant biobased feedstock, representing the first source of renewable aromatic structures. Thanks to its high functionality in aliphatic hydroxyls (Al-OH), phenolic hydroxyls (Ph-OH) and carboxylic acids (COOH), lignin is an attractive precursor to crosslinked polymer materials. Different biobased macromolecular architectures can be designed from lignins, whose end-of-life should also be considered in the context of a circular bioeconomy. To enhance the recyclability of crosslinked polymer networks, the introduction of dynamic linkages to design vitrimers is a promising strategy. In this study, Kraft lignin was chemically modified with succinic anhydride, to prepare a series of modified lignins with a controlled COOH/Ph-OH ratio, exploiting the difference in reactivity between Al-OH and Ph-OH groups. Upon crosslinking with a diepoxy, mixed vitrimer networks with variable ratios between dynamic ester bonds and non-dynamic ether bonds were synthesized. The analysis of their properties evidenced the impact of the non-dynamic linkages on the materials behaviors, including their dynamicity and reprocessing ability. Although the activation energy for bond exchange is increased, non-dynamic linkages do not hinder the reprocessability of these adaptable materials, and provide them high creep resistance. The controlled introduction of non-dynamic linkages appears as a promising strategy to enhance the properties of lignin-based vitrimers.

High creep resistance of (Hf0.2Ta0.2Ti0.2Nb0.2Zr0.2)C high entropy ceramics prepared by spark plasma sintering of the self-propagating high temperature synthesized powders

The compressive creep properties of (Hf0.2Ta0.2Ti0.2Nb0.2Zr0.2)C high entropy ceramic (HEC), prepared by spark plasma sintering of the self-propagating high temperature synthesized powders, are investigated at 1400–1600 °C with stresses of 150∼300 MPa. The as-received HEC was annealed at 2000 °C and 2100 °C for 1 h (HT2000 and HT2100) to eliminated the impurities. The phase composition, microstructure, and dislocation structures are characterized by an X-ray diffractometer, scan electron microscopy, and transmission electron microscopy, respectively. It is found that the steady creep rates of the HT2000 and HT2100 are similar at the same creep conditions, both being 10−8∼10−9 s−1. The creep resistance of both HECs is superior to those of the monolithic carbides. The creep damage includes the grains growth, formation of pores and cracks at the grain boundaries. The creep mechanisms of both HECs include atomic diffusion, grain boundary sliding and dislocation slip. At 1600 °C, Burgers vector of dislocation is a/2 <01‾1>, and the main slip system is a/2 <01‾1>{111}. The excellent creep resistance of the HECs is contributed by the slow atomic diffusion and restricted dislocation motion.

High creep resistance in amorphous/crystalline dual-phase nanostructured CoCrFeNiMn high entropy alloys

Amorphous/crystalline dual-phase metallic materials received great attention owing to their synergistic combination of strength and ductility. However, the mechanisms governing creep deformation in these dual-phase materials are largely elusive. In the present letter, the creep deformation of amorphous/nanocrystalline CoCrFeNiMn high-entropy alloy (HEA) films is investigated through nanoindentation creep testing. It is suggested that dual-phase HEAs exhibit reduced creep strain compared to their monophase counterparts, and even surpass the performance of coarse-grained variants. This behavior arises from diffusion processes within the amorphous phase and the capacity for nucleation/annihilate of dislocations at amorphous/nanocrystalline interfaces. Furthermore, it is proposed that the presence of glass shell significantly influences the creep behavior of dual-phase HEAs.

Controlled creep resistance and melt-flow properties of vitrimers in a facile dual-catalytic system

Interest in vitrimers has increased due to the growing importance of recyclable thermosets. Controlling the flow properties of vitrimers to enhance creep resistance and processability presents challenges, particularly in extending the operating temperature range. Herein, a facile approach using a dual-catalytic system with varied activation energies (Ea) was applied to control the creep and flow properties of vitrimers. We employed an asymmetric dual-catalytic system, where a catalyst with a lower Ea facilitated the formation of a highly cross-linked structure, ensuring high creep resistance at low temperatures, while a catalyst with a higher Ea increased the deformation rate at elevated temperatures. The temperature range with distinct stress-relaxation behaviors were observed when the proper asymmetric dual-catalytic system was applied, where creep was effectively suppressed at lower temperatures, and a dormant catalyst with a higher Ea significantly accelerated the exchange reaction upon activation at higher temperatures. These findings and characterization offer valuable insights into the potential for vitrimer properties control, and vitrimer recycling using diverse catalytic systems.

Exploring the brittle-to-ductile transition and microstructural responses of [formula omitted]−TiAl alloy with a crystal plasticity model incorporating dislocation and twinning

γ−TiAl alloy, with its high specific strength and creep resistance, is ideal for aerospace engines and gas turbines, but its brittleness poses significant manufacturing and processing challenges. To address these issues, this study employs a crystal plasticity finite element method incorporating dislocation and twinning to analyze the brittle-to-ductile transition behavior of γ−TiAl alloy at different temperatures. Additionally, the Bayesian optimization methods are employed to efficiently and accurately obtain parameters related to numerical calculations of crystal plasticity. The results indicate that at room temperature, the high activation resistance of the slip systems in the α2 phase leads to limited slip activity, resulting in poor plasticity. However, at 750 °C and 850 °C, the strength of the slip systems decreases significantly, allowing more α2 phase lamellae in the γ-TiAl alloy to undergo greater plastic deformation. This enhancement in the plastic deformation capacity of the α2phase lamellae reduce the overall deformation incompatibility in the TiAl alloy, thereby improving the overall ductile of the γ-TiAl alloy.

Influence of Si on the Elevated-Temperature Mechanical and Creep Properties of Al–Cu 224 Cast Alloys during Thermal Exposure

The influence of Si content (0.1–0.8 wt.%) on the development of precipitation microstructures and the resultant mechanical and creep properties during thermal exposure, up to 1000 h at 300 °C, in Al–Cu 224 cast alloys, was systematically investigated. The room and elevated temperature yield strength (YS) increased with increasing Si content under the T7 condition, which was attributed to the fact that the Si promoted the precipitation of fine θ′. However, Si increased the coarsening of θ′ during thermal exposure at 300 °C, and the alloys with low Si exhibited a higher YS and creep resistance at elevated temperatures than high Si alloys. The mechanical strength and creep resistance were mainly controlled by the precipitation strengthening of the predominant θ′ phase. Because of the high mechanical strength and creep resistance of the 0.1Si alloy during long-term thermal exposure, the Si level in Al–Cu alloys should be maintained at a low level of 0.1 wt.% for high-temperature applications. The strengthening mechanisms were quantitatively analyzed, based on the characteristics of the precipitate. The predicted YS values under different exposure conditions agreed well with the experimentally measured values.

Controlling the Relaxation Dynamics of Polymer Networks by Combining Associative and Dissociative Dynamic Covalent Bonds.

Dynamic polymer networks offer a promising solution to key challenges in polymers such as recyclability, processability, and damage repair. However, the trade-off between combining facile processability, fast self-healing, and high creep resistance remains a major obstacle to implementation. To overcome this, two very distinct dynamic covalent chemistries, Diels-Alder and transesterification, is combined in a single network. The resulting dual dynamic networks offer an unprecedented set of properties and control over the relaxation times. The system decouples the relaxation dynamics of the network from the spatial motifs, and the tuning of the ratio between chemistries enables to control of the relaxation dynamics over six orders of magnitude. Taking advantage of this control, the composition and rheological behavior is optimized to drastically improve the resolution for extrusion-based additive manufacturing of dynamic covalent networks. Additionally, two well-defined and separated stress relaxation peaks are observed at compositions close to 50% of each dynamic chemistry, accentuating the double character of the system's relaxation dynamics. This atypical situation, enables to preparation of self-healing materials with negligible creep, and with shape-memory properties solely leveraging the two distinct relaxation dynamics, instead of the glass transition temperature or the melting point.

Microstructure evolution and mechanical properties of bioinspired interpenetrating Ti2AlNb/TiAl matrix composite with a crossed-lamellar structure

TiAl alloys with low density, high creep resistance and high temperature performance are considered as candidate materials to replace nickel-based superalloys in the range of 700∼800 °C. However, the intrinsic brittleness of TiAl alloys has always been the biggest bottleneck restricting their development. In this paper, a bioinspired interpenetrating Ti2AlNb/TiAl composite with crossed-lamellar structure was prepared by combining selective laser melting (SLM) and vacuum hot press sintering (HPS) under the condition of 1150 °C/1 h/45 MPa, to improve the strength and toughness of the composite. Meanwhile, the metallurgical defects and microstructure of Ti2AlNb reinforcement skeleton printed under different volume energy densities (VEDs) were investigated, as well as the evolution of the microstructure at the interface region of the composite was systematically studied. What's more, we studied the mechanical properties of the composite including nanoindentation test, room temperature tensile and bending tests. The results show that the VED is 88.89 J/mm3, an almost completely dense reinforcement skeleton (∼99.8 %) is obtained. The interface region can be divided into four different reaction layers, namely LⅠ, LⅡ, LⅢ and LⅣ, due to the diffusion of elements. LⅠ is mainly composed of Othick/thin lath-like phase and O short rod-like phase. LⅡ is mainly composed of B2/β phase, acicular α2 phase and nanoscale ω-Ti3NbAl2 phase. The LⅢ mainly consists of B2/β phase. The LⅣ is composed of α2 phase. The deformability of each phase in the composite: B2/β phase > O phase >γ phase >α2 phase >ω phase. The tensile strength and fracture toughness of bioinspired interpenetrating Ti2AlNb/TiAl matrix composite are increased by 24.0 % and 89.0 %, respectively, compared with TiAl alloy, which is mainly contributed to the strong interfacial bonding between matrix and reinforcement as well as the synergistic effect of Ti2AlNb reinforcement with high strength and toughness.

Development of Ti3SiC2 MAX phase tubular structures for solar receiver applications

Solar receiver tubes are key components of concentrating solar-thermal power (CSP) systems that harvest solar energy. For better efficiency, the Gen3 CSP receivers, which collect heat into a heat transfer fluid, require a temperature exceeding 700 °C during operation and need to perform under extreme conditions of high temperature and high thermal stress. Operators are seeking CSP designs using new high-temperature structural materials with high thermal conductivity and high creep resistance to achieve a design life of 30 years and thus help recover the plant capital cost sooner. MAX phase materials, which consist of an early transition metal element, an A-group element, and carbon or nitrogen, are expected to exhibit high creep resistance as well as high fracture toughness. In this paper, we describe fabricating both (1) dense Ti3SiC2 MAX phase disks and (2) short-length tubes using field-assisted sintering technology (FAST). First, the disk samples that we fabricated are fully dense and contain ≈90 % Ti3SiC2 MAX phase materials and ≈10 % TiC phase materials. We determined a flexure strength of 519 ± 32 MPa by conducting a four-point bending test at room temperature with rectangular bar samples of ≈100 % density. The thermal conductivity of the Ti3SiC2 MAX phase samples, measured by light-flashing analysis, decreases linearly from a value of 41 W·m−1·K−1 at room temperature to a value of 36 W·m−1·K−1 at 650 °C. A solar reflectance measurement of the Ti3SiC2 MAX phase revealed that, temperature increases from 400 to 1400 °C, thermal emittance increases from 0.39 to 0.49, while selectivity decreases from 1.8 to 1.4, respectively. Whereas the surface oxidized MAX phase samples after 100 h exposure to air at 1000 °C exhibit that of SiC.Next, we discuss fabrication of the crack-free Ti3SiC2 MAX phase tubular structures accomplished by using FAST processing in graphite bedding. A Ti3SiC2 MAX phase content of > 95 % with traceable ≈3% remaining TiC phase and ≈15 % porosity were demonstrated after high-temperature annealing. An average fracture strength of ≈250 MPa was determined with Ti3SiC2 MAX phase tubes of ≈85 % density by diametral compression testing at room temperature. Our work demonstrated that using FAST processing to produce Ti3SiC2 MAX phase tubular structures for CSP receiver applications is a viable approach.

Development of a boron-containing reduced activation Ferritic-Martensitic (B-RAFM) steel

Steel will be an essential part of any commercial fusion reactor design. Applications in this area involve extreme conditions, imposing particular performance requirements, such as high operational temperature and creep resistance, and also a limitation on the elements that can be used due to the activation that occurs on interaction with irradiation. This work begins with a steel developed for conventional power plant applications, the IBN1 grade developed by IMPACT (a UK consortium of industrial and academic research organisations). This grade has shown excellent properties at high temperature due to high temperature-stable precipitate phases, but contains several elements that would become radiologically active to a degree that is incompatible with the required disposal routes after exposure to the fusion reactor environment. In this study, modifications of the composition are made to remove these elements, and thermodynamic modelling and experimental assessment of the phases that form are undertaken. In this, we have paid particular attention to the prediction of transformation temperatures (to understand if normalisation and tempering can be applied successfully) and the precipitates, to see if suitable phases that are likely to impart creep strength and other desirable properties would be formed. The modifications made include the removal of Nb, Mo, Ni, Co, Cu and Al from the starting alloy, and the substitution of Ta (intended to form carbides, replacing the effect of Nb). Modifications of the amount of retained elemental components, such as C, Mn and Cr, have been made with Thermo-Calc modelling, to ensure preservation of comparable phase transformation temperatures and microstructures. The predicted changes to the alloy are compared to the observations from experimental investigation, finding that tantalum can substitute for niobium in these systems and form similar carbides with similar distribution in the material, and that reduction of Cr to 8 wt% and increase of C to 0.12 wt% raises the Ae4 temperature to allow a high-temperature heat treatment without δ-ferrite formation. While assessment of the mechanical properties of this alloy would be required, the perspectives for these alloys to perform at high temperature that can be inferred from the microstructure are discussed.

Regulating the microstructures and creep behaviors of an LPSO-containing Mg alloy via heat treatment

The microstructures and creep behaviors of a hot-extruded Mg-Gd-Y-Zn-Zr alloy containing long period stacking order (LPSO) phases prepared by different heat treatment procedures were investigated in this work. Three samples were made, including Sample #1, which was in the as-extruded state; Sample #2, which was preserved at 500 °C for 12 h; and Sample #3, which was preserved at 500 °C for 12 h and 460 °C for 10 h. The average grain sizes of the heat treated samples were much larger than those of the as-extruded samples. The second phases included mainly blocky 18R LPSO phases, lamellar 14H LPSO phases and needlelike ZnZr compounds in the three samples, but Sample #2 had much fewer 14H LPSO phases than the other two samples. The grain boundary migration resulting from the small grain size induced the lowest creep resistance in Sample #1. In contrast, the hardening effects generated from the pyramidal <c+a> dislocations and the dynamic precipitation of dense β’ phases dramatically retarded the cross-slip, resulting in the highest creep resistance in Sample #2. Although the aging treatment introduced numerous 14H LPSO phases in Sample #3, they delayed the dislocation movements to a limited degree, and the creep resistance was inferior to that of Sample #2. Therefore, the creep resistance ultimately decreased in the order of Sample #2 > Sample #3 > Sample #1. It is suggested that the microstructures and creep behaviors of LPSO-containing Mg alloys can be well regulated through appropriate heat treatment, and this work can hopefully offer important guidance for the design of highly creep resistant Mg-Gd-Y-Zn-Zr alloys.

Co-, Ni- and Fe-rich grain-boundary phases enhance creep resistance in θ′-strengthened Al-Cu alloys

Microstructural evolution and creep response were investigated in the cast Al-5.0Cu-0.3Mn-0.2Zr (wt.%) alloy with and without addition of slow-diffusing, intermetallic-forming elements Fe, Ni, or Co. Baseline Al-5.0Cu-0.3Mn-0.2Zr alloy exhibits high creep resistance at 300 °C, up to ∼75 MPa, which is attributed to high-aspect-ratio, intragranular θ′-Al2Cu precipitates that effectively suppress dislocation climb. However, θ′-Al2Cu precipitate-free zones form along grain boundaries upon heat treatment, whose extent is amplified during subsequent creep. Such weak regions experience dislocation creep, leading to strain localization and acceleration of grain-boundary sliding. Adding Ni and Co, individually or in combination, leads to the formation of grain-boundary precipitates (Al9Co2, Al3Ni2) which are resistant to coarsening, thus suppressing the formation of θ′-Al2Cu precipitate-free zones. This microstructure provides high creep resistance at stresses up to 75–80 MPa, with strain rates much lower than in unmodified Al-5.0Cu-0.3Mn-0.2Zr. Adding Fe, which results in extensive decoration of grain boundaries with coarsening-resistant Al7Cu2Fe, and then increasing the Cu content to compensate for the Cu loss to this new phase, leads to a new Al-7.4Cu-1.6Fe-0.3Mn-0.2Zr alloy with creep resistance at 300 °C that surpasses known cast aluminum alloys. Adding Fe to improve the creep resistance of Al-Cu alloys is both cost-effective and sustainable. Our findings offer guidelines applicable to various alloy systems on controlling the evolution of precipitate-free zones and its ensuing effects on creep deformation.

Modification of liquid phase and microstructure of sintered mullite by different additives

AbstractIn the field of ceramics, mullite has drawn plenty of attention due to its low thermal expansion and thermal conductivity as well as its high chemical stability and creep resistance. This work reported the mineral phase, liquid phase, and microstructure evolution of the sintered mullite, using coal‐series kaolin as the raw material and potash feldspar as well as phosphorus pentoxide as additives. The effects of K2O and P2O5 on the content and viscosity of the liquid phase in mullite were calculated using FactSage 8.1. The results showed that the introduction of K2O could inhibit the formation of cristobalite effectively. Adding K2O and P2O5 improved the content of the liquid phase formed during the calcination process. After introducing K2O and P2O5, mullite developed acicular and columnar structures, with average lengths of 9.76 and 7.97 µm, respectively. Furthermore, introducing K2O and P2O5 improved the physical properties of mullite significantly.

The Irradiation Effects in Ferritic, Ferritic-Martensitic and Austenitic Oxide Dispersion Strengthened Alloys: A Review.

High-performance structural materials (HPSMs) are needed for the successful and safe design of fission and fusion reactors. Their operation is associated with unprecedented fluxes of high-energy neutrons and thermomechanical loadings. In fission reactors, HPSMs are used, e.g., for fuel claddings, core internal structural components and reactor pressure vessels. Even stronger requirements are expected for fourth-generation supercritical water fission reactors, with a particular focus on the HPSM's corrosion resistance. The first wall and blanket structural materials in fusion reactors are subjected not only to high energy neutron irradiation, but also to strong mechanical, heat and electromagnetic loadings. This paper presents a historical and state-of-the-art summary focused on the properties and application potential of irradiation-resistant alloys predominantly strengthened by an oxide dispersion. These alloys are categorized according to their matrix as ferritic, ferritic-martensitic and austenitic. Low void swelling, high-temperature He embrittlement, thermal and irradiation hardening and creep are typical phenomena most usually studied in ferritic and ferritic martensitic oxide dispersion strengthened (ODS) alloys. In contrast, austenitic ODS alloys exhibit an increased corrosion and oxidation resistance and a higher creep resistance at elevated temperatures. This is why the advantages and drawbacks of each matrix-type ODS are discussed in this paper.

Жароміцні інтерметалідні сплави та особливості їх легування

The work considers the prerequisites for the development of creep-resistant and heat-resistant alloys, based on intermetallics, taking into account the optimal combination of their physical and mechanical properties, as well as structural characteristics. It is shown that there is a sufficient number of intermetallics, which have a density lower than iron-based alloys, which, in combination with high melting temperatures and heat resistance, makes them promising materials for aerospace application, in particular, for gas turbine engine parts manufacturing. The most suitable creep-resistant and heat-resistant intermetallics can be called aluminides and silicides of titanium, nickel and molybdenum. For these compounds, it is possible to combine high values of specific strength with alloying-favorable types of crystal lattice. One of the most important and common creep-resistant alloys based on intermetallics is Ni3Al with FCC lattice. For this material, complex optimized alloying is the main way to increase creep resistance. The heat resistance of such alloys is significantly increased by applying ceramic coatings. Titanium aluminides Ti3Al and TiAl mainly have only a low density among the advantages. Their fragility at room temperatures and tendency to superplasticity at high temperatures significantly limits their application. The impact of disadvantages may be reduced by applying thermomechanical processing of such materials, which aims to change their structure. Alloying titanium aluminides with a large amount of niobium was chosen as a solution that significantly reduced marked week sides of Ti-Al intermetallic alloys. As a result, this led to the creation of a new alloy based on intermetallic Ti2AlNb with a high set of operational characteristics. Mo-Si and Mo-Si-B can be considered as one of the most perfect systems for creating heat-resistant intermetallic alloys. They combine an acceptable density, high creep and heat resistance, which can be additionally increased by reinforcing with ceramic particles. Keywords: intermetallic-based alloys, creep resistance, alloying, Ni-Al, Ti-Al, Mo-Si, Mo-Si-B.

Compression creep behaviors of GH4169 cylinder entangled wire material at elevated temperatures

As a nickel-based alloy, GH4169 has the properties of excellent corrosion resistance, high temperature oxidation resistance and high creep resistance. In this paper, the compression creep behaviors of cylinder entangled wire materials (CEWMs) made from metal wires (GH4169 nickel-based alloy, 304 stainless steel) were investigated at elevated temperatures (from 400 °C to 500 °C). The performance degradation of the two materials was evaluated by the variation amplitude of four mechanical properties parameters and material characterization methods. The results indicated that both of 304 CEWMs and GH4169 CEWMs suffered a significant performance degradation at elevated temperatures, and both of the two CEWMs showed a much serious performance degradation above 450 °C (tempering temperature). Compared to the 304 CEWMs at the tested temperatures, the GH4169 CEWMs obtained better creep resistance. It is therefore concluded that the GH4169 CEWM is an excellent material that can replace the commonly used 304 CEWM at elevated temperature work conditions.

Experimental Investigation and Optimization of Coaxiality Error Analysis with CNC Turning Process on Delrin for Assembly Fit

This paper mainly deals with the machining operation like turning operation, Material Removal Rate and Surface Roughness are the important parameter which is to be considered for quality product. The material selected for the experiment is DELRIN 500. Turning is one of the important processes that is widely used to create cylindrical components and it is also used for surface finish the product to make it smooth. Nowadays, plastic materials are widely used for making variety of components. To make a component with high dimensional accuracy, turning operation is used. The main concerns of turning are tooling cost and the effect of process on machinability characteristics. It can be seen that the output responses value has a minimum roughness average and a high degree of geometrical quality precision. High degree surface finish is induced by medium speed, feed rate, and small nose radius. The coaxial error was minimized by using medium speed, feed and larger nose radius. Experimentally found that third specimen (RPM -750) (FEED -0.08 mm/Rev) and (NOSE RADIUS 0.8) obtained minimum geometrical error along with minimum Surface roughness. Delrin is a crystalline plastic that offers an excellent balance of properties that bridge the gap between metals and plastics. Delrin possesses high tensile strength, creep resistance and toughness. It also exhibits low moisture absorption

Internally cooled tools as an innovative solution for sustainable machining: Temperature investigation using Inconel 718 superalloy

Machining is a process that involves intense heat generation at localized points within the tool-chip interface. This leads to elevated temperatures, which can be detrimental to cutting tools. This issue becomes even more crucial when dealing with superalloys like Inconel 718, as they exhibit high shear strength and good creep resistance. Consequently, a significant amount of energy is expended, increasing the cutting temperature. Until now, the primary technique employed to address this issue has been using Cutting Fluids (CFs). In machining, a portion of costs is attributed to fluid handling. It also contains harmful elements that can pose health risks, potentially leading to conditions such as cancer. Moreover, the toxic components can contribute to environmental degradation when improperly disposed of. Therefore, this study proposes an innovative cooling technique called Internally Cooled Tools (ICTs). The ICTs employ an internally circulating coolant fluid through closed cooling channels within the cutting tools, eliminating fluid dispersion into the atmosphere. The main objective was to compare the performance of ICTs in controlling the tool-chip interface temperature during Inconel 718 turning using hard metal tools. For this purpose, a complete factorial experimental design (25) was utilized, with the response variable being the temperature measured by the tool-work thermocouples technique. Beyond that, a sustainable assessment was performed using the Pugh Matrix method. Many key sustainable factors were evaluated related to three atmospheres, cutting fluids in abundance – CFA, dry machining, and ICT. The data base used was a depth literature investigation together with results found in this work. The main findings of this entire work demonstrated that an increase in cutting parameters corresponded to an increase in temperature, as anticipated. TiNAl coating reduced the temperature by up to 10% compared to uncoated tools. Similarly, applying ICTs led to temperature reductions of up to 17% compared to dry machining conditions. The Pugh Matrix made considering 12 factors showed that ICT (14 points) was the most sustainable lubri-cooling method in comparison to CFA (3) and DM (5). Ultimately, ICTs showed to be a promising eco-friendly method. It outperformed conventional methods, showcasing a remarkable heat dissipation capacity. As a result, further studies are warranted to delve deeper into this promising approach.