Alloy Additions Research Articles

Influence of Alloy Addition on Mechanical Properties of Low Alloy Steel in Powder Metallurgy Gears

Influence of Alloy Addition on Mechanical Properties of Low Alloy Steel in Powder Metallurgy Gears

Comparative analysis of laser power, pure titanium, and titanium alloy effects on dendrite growth and surface morphology of TiO2-ceramic

Despite several challenges, including the inherent brittleness of ceramics, inadequate melting of the powder, and the formation of microstructural defects, laser powder bed fusion remains a promising method for ceramic fabrication. This research looks at the intricate relationship between laser power as a dominant factor in the energy density, the influence of pure titanium (Ti) and titanium alloy (Ti-6Al-4V) additives on the laser fabrication of TiO2-based ceramics, and the resultant microstructural aspects, with a particular emphasis on dendritic growth and solidification defects. The research findings revealed that changing the laser energy density has a substantial influence on the dendrite growth and solidification rate of TiO2 ceramic. However, in addition to optimizing the laser power, the addition of metal material additives also plays a significant role in regulating the melting state and controlling the part defects in ceramics. The findings support that the mixing of pure titanium showed a relatively favorable influence, enhancing the melting condition of TiO2 and yielding a smooth surface with reduced defects. Conversely, the addition of a titanium alloy (Ti-6Al-4V) has a comparatively lower positive effect and led to the formation of substantial dendrites, solidification shrinkage, and significant fractures. The change in the scanning strategy from zigzag to island has no noticeable effect on the surface morphology and dendrite formation but contributes to controlling the spattering and crack propagation.

Analysis of research on abrasive wear of vermicular cast iron

The paper analyzes and discusses the orientations of researchers regarding the abrasive wear of vermicular cast iron. The analysis was related to the shape of graphite occurrence in cast iron, the change in the matrix and the change in chemical composition, and the impact of these changes on wear under dry and wet friction conditions. Compact graphite cast iron is tested for use in machine and device parts such as cylinders and piston rings, discs, shafts and bearings. It was found that the improvement of abrasive wear of vermicular cast iron is influenced, among others, by the shape of graphite, the alloy addition in the form of tin, as well as the change of the matrix in vermicular cast iron to an ausferritic one. Summarizing the analysis of research carried out by a number of authors, it would be necessary to continue research on the abrasion resistance of this material, and it would also be advisable to include issues related to the warping and deformation of samples as a result of heating and cooling of cast iron.

Al-Ti-C (CNTs) master alloys improve room temperature and high-temperature mechanical properties of ZL205A alloy

The insufficient high-temperature properties of Al-Cu alloys represent a significant obstacle to their further development. The use of master alloy refiners can enhance the mechanical properties while refining the grains. This paper describes the preparation and characterization of Al-Ti-C (CNTs) master alloys containing submicron TiC particles through the aluminum melt reaction method, utilizing graphite powders (GPs) and (CNTs) as carbon sources,respectively.The effects of these two types of intermediate alloys on the microstructures and high-temperature mechanical properties of the ZL205A alloy were investigated at varying additive amounts. The results indicate that the Al-Ti-C (CNTs) master alloys contain TiC particles measuring up to 183 nm and 480 nm, respectively, with the Al-Ti-CNTs demonstrating a superior effect on the refinement of the ZL205A alloy. The optimal mechanical properties were achieved upon the addition of 0.3 wt% of the master alloy to the ZL205A alloy. The mechanical properties improved from 341.53 MPa (yield strength), 371.68 MPa (tensile strength), and 3.3 % elongation without the addition of master alloys to 413.20 MPa, 471.82 MPa, and 11.2 % with the addition of Al-Ti-CNTs and to 440.85 MPa, 492.61 MPa, and 10.8 % with the addition of Al-Ti-C, respectively.At a high temperature of 300°C, the mechanical properties of the ZL205A alloy improved from 144.0 MPa and 10.8 % (Al-Ti-C) to 174.87 MPa and 11.2 %, and 195.1 MPa and 13.8 % (Al-Ti-CNTs). The TiC particles generated in situ under a different carbon sources demonstrated distinct mechanisms in the grain refinement of the ZL205A alloy. TiC (GPa) with a larger size primarily impeded the further growth of grains, while TiC (CNTs) promoted the formation of crystalline nuclei and heterogeneous nucleation sites, thereby achieving grain refinement. Large-sized TiC particles prepared using graphite as the carbon source hindered further grain growth, whereas TiC produced using carbon nanotubes promoted the formation of nuclei and heterogeneous nucleation sites, resulting in grain refinement. In addition, both types of TiC particles contribute to the densification and strengthening of the ZL205A alloy through fine grain strengthening, precipitation strengthening, Orowan strengthening, load transfer strengthening, the pinning effect, and thermal mismatch strengthening. However,TiC(CNTs) exhibits a greater contribution to strength due to its high quantity and small size.

Strengthening effects from Mg and Ni in Al-mischmetal eutectic alloys: Insights from microstructures and Bayesian analysis

This study investigates, both experimentally and via machine-learning modeling, the strengthening mechanisms and effects of Mg and Ni additions to Al-MM (mischmetal, a sustainable Ce+La+Nd mixture to replace Ce) alloys, aiming to develop creep- and coarsening-resistant Al-MM-Mg-Ni alloys with a focus on twin eutectic co-solidification microstructures. Based on near-eutectic Al-9MM (wt%) alloy, the Mg and Ni additions introduce solid-solution and eutectic strengthening, respectively. Ternary hypo-eutectic Al-9MM-0.25/0.5/0.75Mg variants improve hardness up to 592 MPa. Ternary Al-9MM-2/4Ni display hypo-eutectic microstructures. Al-9MM-2Ni shows separated growth of Al11MM3 and Al3Ni eutectic phases, while Al-9MM-4Ni features finely intertwined Al11MM3-Al3Ni fibers from co-solidification. The hyper-eutectic Al-9MM-5Ni contains primary Al3Ni particles alongside the intertwined fibers, raising the hardness to 739 MPa. Finally, quaternary Al-9MM-0.5/0.75Mg-4/4.5Ni alloys maintain hypo-eutectic microstructures with a significant increase of hardness to 929 MPa. The series Al-9MM, Al-9MM-0.75Mg, Al-9MM-4Ni, and Al-9MM-4.5Ni-0.75Mg exhibits increasing tensile yield strengths of 70, 83, 88, and 105 MPa, with decreasing ductility of 12.0, 5.8, 2.0, and 0.8 %. All Al-9MM-Mg-Ni alloys exhibit excellent hardness retention and coarsening resistance after thermal exposure at 300 or 350°C for up to 11 weeks. A machine-learning model accurately predicts the alloy's hardness evolution under thermal exposure. Feature analysis quantitively shows the strengthening impact of MM, Ni, and Mg addition and demonstrate enhanced strengthening retention, under thermal exposure, of Al11MM3 over Al3Ni, alongside the beneficial effects of Mg homogenization. At 300 °C, Al-9MM-Mg-Ni alloys demonstrate higher creep resistance than most precipitation-strengthened Al-Sc-Zr-based alloys and solid-solution-strengthened Al-Mg alloys, with Al-9MM-4Ni as the best performer.

Formation of Bainite in a Low‐Carbon Steel at Slow Cooling Rate – Experimental Observations and Thermodynamic Validation

Bainitic microstructures in high‐strength steels are obtained either by continuous cooling or isothermal holding. Both scenarios necessitate faster cooling to keep the parent austenite phase untransformed till the bainite‐start temperature. The present study reports the development of bainitic microstructure in a low‐carbon steel with minimal alloying additions, under continuous cooling at very slow rates, similar to furnace cooling. For understanding the related transformation pathways, samples from the forged‐steel ingot are austenitized and cooled at different rates, viz. water quenching, air cooling, and furnace cooling. Microstructural characterization reveals development of acicular microstructures in all samples including the forged one, with gross absence of carbides. X‐ray diffraction confirms the ferritic nature of acicular plates and also indicated retained austenite present in some samples, the content of which could be correlated to the extent of bainitic transformation. Thermodynamic calculations together with microstructural observations (e.g., ferrite plate size) and hardness data established the development of fully martensitic microstructure on water quenching, while that of a mixed microstructure comprising predominantly of bainite in the forged, air cooled, and furnace‐cooled condition. The aforementioned findings could have wider implications in developing fully bainitic microstructures in large components, where uniform rapid cooling is not practically feasible.

Analysis of the structural, magnetic, thermoresistive, and thermoelectric properties of the microcomposite (Ni0.1Zn0.9O)1-x ─(Ni50Mn37Sn10Cu3)x

The present study aims to evaluate the impact of adding the Ni50Mn37Sn10Cu3 alloy to a Ni0.1Zn0.9O ceramic matrix on structural, morphological, magnetic, thermoresistive, and thermoelectric properties. The Ni0.1Zn0.9O system was obtained through the combustion reaction method. The microcomposite (Ni0.1Zn0.9O)1-x (Ni50Mn37Sn10Cu3)x, where x = 0, 2.5, 5, 10, 20, and 40, was successfully with sintering at 1223K. The microcomposite samples exhibited a good linear relationship between the logarithm of electrical resistivity (lnρ) and the reciprocal of absolute temperature (1000/T) at 300K–360K. The values of the constants A, B, and C are characteristic of NTC behavior, and their curves closely approximate the experimental data. The resistivity ρ305, and the coefficients β, α, and SF obtained from the thermistors are approximately 0.12 MΩcm to 7.28 MΩcm, 5026 K–8436 K, 0.017 K-1 to 0.024 K-1, and 1.03 to 1.4, respectively. The magnetic properties of the samples increased as the alloy addition content increased, with values ranging from 51.7 to 63 for Hc, 0.03 to 1.34 for Ms, and 2∙10−4 to 0.13 for Mr. The values of the band gap remained in the range of 2.23–2.77 eV. The magnetic, thermoelectric, and thermoresistive characteristics can be adjusted to the desired value by altering the content of Ni50Mn37Sn10Cu3 in the Ni0.1Zn0.9O matrix. The results demonstrate the potential of the studied system for NTC performance materials, with magnetic and thermoelectric properties. There is significant potential for the development of new microcomposite materials, but it also opens up new research perspectives in the field, especially related to microcomposites containing Heusler alloys.

Phase Equilibria Study of the MgO–CaO–SiO2 Slag System with Ferronickel Alloy, Solid Carbon, and Al2O3 Additions

Phase Equilibria Study of the MgO–CaO–SiO2 Slag System with Ferronickel Alloy, Solid Carbon, and Al2O3 Additions

Effect of surface area on the wear properties of Al-based automotive alloy and the role of Si at eutectic level

The efficiency of an engine material is closely correlated with its surface area. In order to investigate wear properties, effect of surface contact area as well as silicon addition at the eutectic level of Al-Cu-Mg alloy has been studied. This test is performed under room atmosphere and dry sliding conditions using a standard pin-on-disk apparatus. Weight reduction method is adopted to measure the wear rate in microns to get more accurate results. A load varying from of 5 to 50 N and a constant sliding speed of 0.77 ms−1 are maintained throughout the test. The test results show that a lower contact surface area has a negative impact on the wear properties having higher wear rate, while the coefficient of friction of the alloy and Si addition into the alloy improve the properties to some extent. Reduction of the contact surface area increases the unit pressure and decreased material volume causes softening of the alloy matrix, resulting in a higher wear rate and coefficient of friction. The Si addition offers such an improvement mostly for an increase in strength via the Si-rich intermetallic formation. A microstructural study confirms a lower abrasive wear with a minor plastic deformation on the worn surfaces of Si added alloy and wear with higher contact surface. The Si-added alloys contain the fine and strong Si-rich intermetallic, which are responsible for such a smooth worn surface.

Optimization of Laser Cladding Parameters for High-Entropy Alloy-Reinforced 316L Stainless-Steel via Grey Relational Analysis

Laser cladding technology serves as a pivotal technique in industrial production, especially in the realms of additive manufacturing, surface enhancement, coating preparation, and the repair of part surfaces. This study investigates the influence of metal powder composition and processing parameters on laser cladding coatings utilizing the Taguchi orthogonal experimental design method. To optimize the laser cladding parameters, multi-response grey relational analysis (GRA) was employed, aiming to improve both the microhardness and the overall quality of the coatings. The optimal parameter combinations identified through GRA were subsequently validated through experimental tests. The results reveal that the microhardness and quality of the coatings are substantially influenced by several critical factors, including the powder feed rate, laser power, high-entropy alloy (HEA) addition rate, scanning speed, and substrate tilt angle. Specifically, the powder feed rate exerts the most significant effect on the microhardness, dilution rate, and average contact angle. In contrast, laser power primarily impacts the mean contact angle difference. The HEA addition rate notably affects the mean contact angle difference, while the scanning speed affects the microhardness and the substrate tilt angle influences the average contact angle. The results of the validation experiment showed a deviation of only 0.95% from the predicted values, underscoring the efficacy of the grey relational analysis (GRA) in optimizing the laser cladding process parameters. The methodology presented in this paper can be applied to determine the ideal processing parameters for multi-response laser cladding processes, encompassing applications such as surface peening and surface repair.

Effect of Ash and Sulphate on Corrosion of Ni-Based Alloys in a Simulated Oxyfuel Combustion Environment

AbstractAlloys of Ni–25Cr–(2Mn–1Si) under mixed deposits of ash + (0, 10, 50 and 90) wt% sulphate were exposed to an Ar–60CO2–20H2O gas at 650 and 750 °C for up to 300 h, forming both protective chromia and regions of Ni-rich oxide. The presence of ash + sulphate mixtures improved Ni–25Cr alloy protection, increasing surface coverage by thin, protective chromia compared with the deposit-free condition. Increasing sulphate proportions in these mixtures led to an accelerated chromia scale growth and reduced internal oxidation zone (IOZ). These beneficial effects were more significant at 750 °C, where surface coverage by the protective scale was increased, and a chromia band was formed beneath nonprotective regions at the IOZ-substrate interface. Alloy additions of Mn and Si generally slowed the growth of outer NiO and IOZ but did not lead to exclusive chromia scale formation.

Development of Cast AZ63 Magnesium Alloys for Cathodic Protection Applications via Alloying Additives

Development of Cast AZ63 Magnesium Alloys for Cathodic Protection Applications via Alloying Additives

Effect of V-VIB group ternary elements on the properties of Ti2AlM-type O-phases: A first-principles study

Understanding the underlying constitutional mechanisms for the stability of complex phases and comprehending it is crucial to find new materials with desired mechanical and physical properties. In TiAl-alloys with ternary alloying additions orthorhombic phases can form but the effects of different alloying elements on their stability and other properties are only scarcely known. We present a comprehensive study using density functional theory (DFT) within the generalized gradient approximation (GGA) with the Perdew–Burke–Ernzerhof (PBE) method to determine energetic, and mechanical stability criteria and evaluate the electronic densities of states (DOS) and band structures to understand bonding behavior. The stability of Ti2AlM, as a bulk O-phase in ternary TiAl-based systems is predicted by investigating VB (V, Nb, and Ta) and VIB (Mo, W) group elements as ternary addition M. The electronic density of states and band structure indicate that the ternary elements addition causes charge redistribution through the formation of a bond, which significantly alters the stability and mechanical properties. All investigated compounds exhibit negative formation energies and the calculated elastic constants reveal that all are mechanically stable. For the different O-phase types investigated Ti2AlMo is the most stable and Ti2AlV the least stable when comparing energies of formation. The obtained elastic moduli and Pugh's ratios support the idea that Ti2AlM (M = V, Nb, Ta, Mo, and W) O-phases have attractive mechanical characteristics and exhibit ductility. Among all the systems investigated, Ti2AlMo, and Ti2AlW provide the highest increase in B, G, and E values. Based on the elastic constants also indicators for the mechanical properties, such as Poisson's ratio (ν), and Pugh ratio G/B, are calculated. According to our calculations, the brittle Ti2AlV is harder than the ductile Ti2AlMo. Based on the results of the present study, the Ti2AlM type O-phase is considered a promising constituent for designing new materials in the ternary Ti–Al-M system.

Analysis of Tribological Properties of Hardfaced High-Chromium Layers Subjected to Wear in Abrasive Soil Mass.

This article presents the results of abrasion wear resistance tests of wear-resistant steel and surfacing under laboratory conditions and natural operation. Abrasion wear resistance determined on the basis of the study by determining geometrical characteristics of the alloying additives using computer image analysis methods, as well as examining the changes occurring on the surface of the workpieces and their wear intensity. Based on the results obtained from laboratory tests, it was noted that AR steel exhibited 14 times greater wear than the padding weld. This wear is affected by alloy additives, which, for the padding weld, are chromium additives. The microstructure image shows that soil mass had a destructive effect mainly on the matrix of the material, whereas in the areas with high concentrations of chromium precipitates, this effect was significantly weaker. The operational test results showed that within the area of the tine subjected to hardfacing, the material loss was lower than that for the same area of the tine in the as-delivered state. For the hardfaced tine, a 7% loss of volume was noted in relation to the operating part before testing and following the friction process. However, for the operating part in the as-delivered state, this difference amounted to 12%.

Development of a DFT-driven thermodynamic framework for ferrous alloy electrochemistry in acidic media

The electrochemical behavior of different phases (ferrite, austenite, martensite, cementite) and effect of alloying addition in ferrous alloys was examined in acidic media. A comprehensive thermodynamic model, incorporating first-principles calculations, was constructed to predict cathodic and anodic behavior in acidic environments. Cementite emerged as the most corrosion resistant phase, followed by austenite, while ferrite displayed the least resistance. Interestingly, carbon additions improved corrosion resistance in ferrite and austenite. Alloying with Cr, Mn, and Cu was observed to hinder anodic dissolution, reducing electrochemical activity. Finally, the thermodynamic framework provides a reliable and efficient screening tool that can accelerate the development of alloys and coatings.

Vacuum processing temperature effect on highly coercive recycled NdFeB permanent magnets with Pr-based alloy addition

This study presents a modified method for recycling NdFeB scrap magnets, producing up to 100 kg of recycled sintered NdFeB magnets per batch. By adding a Pr-based alloy to N40H-grade NdFeB scrap and optimizing vacuum sintering and heat treatment conditions, we enhanced the magnetic properties and corrosion resistance of the recycled magnets. Various analyses, including BH Tracer measurements, FE-EPMA, accelerated corrosion tests, and C/N/O content analysis, evaluated differences in magnetic properties, microstructure, corrosion resistance, and impurity content. Optimal recycling involved vacuum sintering at 1085 °C, followed by heat treatments at 900 °C and 470 °C. Recycled magnets with PrCoGa alloy showed superior properties, such as an intrinsic coercivity (iHc) of 1414 kA/m, remanence (Br) of 1.290 T, and a maximum magnetic energy product ((BH)max) of 315.4 kJ/m, meeting N40H standards. Accelerated corrosion tests also indicated enhanced corrosion resistance in recycled magnets with Pr90Co8Ga2 alloy. This research offers a commercially viable approach for NdFeB magnet and rare earth element recycling.

The Effect of Alloy and Flux Addition Practices on Inclusion Composition in Si-Mn-Killed Low-C Steel

The Effect of Alloy and Flux Addition Practices on Inclusion Composition in Si-Mn-Killed Low-C Steel

Research on Alloying Elements' Influence on CuETP-Grade Copper's Mechanical and Electrical Properties.

The continuous industrial development that occurs worldwide generates the need to develop new materials with increasingly higher functional properties. This need also applies to the basic material for electricity purposes, which is copper. In this article, we carry out studies on the influence of various alloying elements such as Mg, In, Si, Nb, Hf, Sb, Ni, Al, Fe, Zr, Cr, Zn, P, Ag, Sc, Pb, Sn, Co, Ti, Mn, Te and Bi on the electrical and mechanical properties of ETP-grade copper. The research involves producing copper alloys using the gravity die casting method with alloy additions of 0.1 wt.%, 0.3 wt.% and 0.5 wt.%. All resulting materials are cold-worked to produce wires, which are subsequently homogenized and annealed. The materials produced in this manner undergo testing to determine their specific electrical conductivity, tensile strength, yield strength, elongation and Vickers hardness (HV10 scale).

A value of information approach to recycling

Uncertainties with respect to the chemical composition of scrap limit its suitability as an input to recycling. This study offers an alternative approach in dealing with this concern and explores the hypothetical case where this uncertainty is nonexistent. The effect of fully knowing the scrap composition is simulated using an optimization software adopted to scrap-based, stainless-steel production. Through the systematic implementation of this information-driven model in the studied cases, the results suggest that with access to perfect information, recycling incentives can be realized. Essentially, the steel scraps’ consumption increased since it was possible to select and combine scrap quantities with varying composition profiles to achieve the targeted product compositions. This also meant that elements already in the scrap were allocated in a manner that was less dependent on pure alloy additions. Being able to demonstrate the value of information on scrap composition could rationalize upgrades on current scrap management systems.

Effect of Nd-M (M = Al/Co) alloys addition on microstructures and magnetic properties of hot deformed CeFeB magnets

In this study, the magnetic properties, thermal stabilities, elemental distributions and phase transition temperatures of hot deformed CeFeB magnets were investigated by adding 20 wt% of Nd85Al15 and Nd64Co36 alloys, respectively. The results revealed that the addition of low melting point alloys efficiently enhanced the comprehensive magnetic performance and thermal stability of the CeFeB magnets. The optimal magnetic properties were obtained with the addition of 20 wt% Nd85Al15. Compared to the original sample, the coercivity increased from 104 kA/m to 604 kA/m, and the maximum magnetic energy product increased from 8 kJ/m3 to 34 kJ/m3. The incorporation of Nd-Al/Co alloys effectively reduced the area fraction of the coarse grain region and facilitated a more uniform distribution of the RE-rich phase. TEM observations demonstrated that Nd partially replaced Ce, leading to the formation of (Nd, Ce)2Fe14B hard magnetic phase. Additionally, the analysis of the M–T curves indicated the presence of two Curie temperature points for Nd85Al15 and Nd64Co36 added CeFeB hot deformed magnets. The addition of Nd85Al15 improved the fluidity of the RE-rich phase, thereby enhancing the coercivity. Conversely, the incorporation of Nd64Co36 resulted in the entry of Co elements into the main phase, contributing to improved thermal stability.