Effect Of Different Alloying Elements Research Articles

Effects of alloy composition in traditional Japanese shakudo patination.

Japanese craftspeople have dominated the art of patinating copper-alloys since the 15th century, using precise alloy compositions and complicated patination processes in different hot solutions to create a variety of colours on swords fittings such as tsuba. While this complex tradition is increasingly popular in the East, the reasons behind the choices made by craftspeople in the selection of the components of the alloys and are still not fully understood. This paper investigates the effect of different alloying elements (tin, gold, and silver) on the resulting patina. Experimental results are compared with optical and compositional analyses on historical Japanese artefacts, confirming the effects of the different alloying elements on the patina characteristics and colour. The absence of tin and the presence of gold limit the growth of an oxide layer and promote the formation of a thin patina characterised by a smooth appearance without visible grains. Therefore, a limited thickness of the patinas is a key aspect for the production of the desired colour and appearance of the patinas. The first colorimetric analysis on historical Japanese artefacts demonstrates the influence of gold, silver and tin in the final patina colour, validating the observations in the experimental replicas.

The Effects of Alloying Elements on the Bonding Strength of Diamond/Carbide/Cu Interface Based on First‐Principles Calculations

The effects of different alloying elements (Ti, Zr) on the bonding strength of the diamond (111)/carbide (111)/Cu (111) interface system have been systematically investigated by means of first‐principles calculations based on density functional theory. It is found that the metal (Ti, Zr)‐terminated carbide is more likely to participate in the formation of the carbide (111)/Cu (111) and carbide (111)/diamond (111) interface. However, the C‐terminated carbide (111) interfaces have higher bonding strength compared with the metal (Ti, Zr)‐terminated carbide interfaces. In the Cu/carbide/diamond interface system, the bonding strength of carbide/Cu interface is lower than that of the carbide/diamond interface, which means the Cu/carbide/diamond interface failure first occurs in the carbide/Cu interface. According to the charge density, the stronger charge interaction between Zr and Cu causes higher bonding strength of ZrC/Cu interface compared with TiC/Cu interface. Therefore, the Cu/ZrC/diamond interface has higher bonding strength compared with the Cu/TiC/diamond interface. The Csp (carbide)–Csp (diamond) covalent bond and the metal (Ti3d, Zr4d)–Csp (diamond) covalent bond are formed at the diamond/carbide interface, while the Cu3d–Csp (carbide) covalent bond and the metal (Ti3d, Zr4d)–Cu3d metallic bond are formed at the Cu/carbide interface.

Lattice Distortion and Piezoelectricity Enhancement in GaN by Alloying with Group III and Rare‐Earth Elements: A Comparative Experimental Study

The lattice of wurtzite nitrides such as gallium nitride (GaN) and aluminum nitride (AlN) is distorted by alloying with scandium (Sc). This lattice distortion, which entails a decrease in the lattice constant ratio c/a, leads to a significant improvement in piezoelectricity and the appearance of ferroelectricity, which are attractive properties for material applications. However, systematic studies on the effect of different alloying elements on the lattice distortion of wurtzite nitrides are scarce and restricted to theoretical investigations. Herein, the experimental investigation of the lattice distortion and its influence on the piezoelectricity of cosputtering‐prepared thin films of GaN alloyed with group III and rare‐earth elements other than Sc, that is, yttrium, dysprosium, and ytterbium is described. All the investigated elements greatly reduce the lattice constant ratio of GaN from 1.63 to 1.61 and cause a twofold increase in the piezoelectric charge coefficient. Therefore, it is indicated in the experimental results that alloying with elements other than Sc also results in the distortion of the crystal lattice and the enhancement of the piezoelectric properties of GaN. Furthermore, regardless of the particular alloying element used, a correlation between lattice distortion and piezoelectricity is experimentally demonstrated.

Effects of alloying elements on the interfacial segregation of bismuth in tin-based solders

Sn-Bi solders are potential candidates for replacing traditional lead-based solders in electronic packaging due to their low melting points, superior wettability, and mechanical properties. The grain coarsening due to the interfacial Bi segregation is a vital issue that affects the reliability of Sn-Bi solder joints. Through first-principles calculations, this study systematically revealed the effects of different alloying elements on the interfacial segregation of Bi towards Sn(100) surface. Bi tends to segregate to the top-surface of Sn due to the formation of vacancies on Sn surface. However, doping alloying elements into the Sn-Bi solders could effectively suppress the interfacial Bi segregation. The presence of elements such as Pd, Pt, and Au located at the adjacent surface layer of Bi could inhibit the Bi precipitation, by apparently increasing the segregation energies of Bi to the Sn surface. The results can be interpreted by the enhanced bond orders and charge transfer between Bi, alloying elements, and their neighboring Sn atoms. This study could provide valuable insights into the design of multi-component Sn-Bi solders with minor alloying elements doping in the future.

Fundamental insights on ductile to brittle transition phenomenon in ferritic steel

Ductile to brittle transition (DBT) is a well-known phenomenon responsible for deteriorating the low temperature fracture toughness of ferritic steels. It is unambiguous to state that the transition phenomenon is a direct consequence of the strong temperature and strain rate sensitivity of flow stress, which in turn is regulated by the thermally activated motion of screw dislocation at the atomic scale. Due to very high Peierls stress, screw dislocation motion is accompanied by the nucleation and propagation of kink-pairs along the dislocation line. Thus, the activation energy required for kink-pair nucleation is an essential ingredient for correctly predicting the flow stress sensitivity and hence the ductile to brittle transition temperature (DBTT) of ferritic steel. However, experimental determination of kink-pair activation energy is rather tedious and there exists a strong discrepancy between atomistic simulation results (using Density Functional Theory and empirical potentials). Therefore, the present review is aimed at understanding the mechanism of screw dislocation motion in BCC Fe lattice and comparing the results obtained for kink-pair activation energy through experiments and simulations. The effect of different alloying elements on the overall flow stress sensitivity of Fe is also discussed with reference to the interaction of screw dislocation with solute atoms or clusters. Finally, the importance of screw dislocation on predicting the DBTT is explored to identify the present knowledge gaps and the future research directions.

Effect of Zr, Ti, Ta and Mo addition on high-temperature oxidation and hot corrosion behavior of NiAlY alloys

NiAlY alloys with the addition of Zr, Ti, Ta and Mo were prepared by arc melting. The oxidation and NaCl-induced hot corrosion behavior of the alloys were investigated at 650 ℃, with the focus on the effect of element-doping and phase. With the addition of Ti, Ta and Mo, the oxidation resistance of the tested alloys was effectively enhanced compared to the undoped NiAlY alloy. However, the NiZrAlY alloy showed very poor oxidation resistance. Under the NaCl-induced hot corrosion test, the NiTaAlY and NiMoAlY alloys exhibited an improved hot corrosion resistance, while the NiZrAlY and NiTiAlY alloys showed very poor hot corrosion resistance. Moreover, the NiAl and Ni 5 Y phases exhibited different behavior during the oxidation and NaCl-induced hot corrosion tests. • A new type NiXAlY system doped with different alloying elements was designed in this work. • The oxidation and hot corrosion behaviors of NiAlY alloys with different alloying elements addition such as Zr, Ti, Ta and Mo were investigated at 650 ℃. The effects of different alloying elements on oxidation and hot corrosion resistance were investigated. • Y displayed a negative effect in both oxidation and hot corrosion resistance. The degradation mechanisms of Y-rich areas in the oxidation and hot corrosion tests were different.

First-principles study on effect of alloying elements on heterogeneous nucleation of reverse austenite on Cu precipitation

The mechanical properties of ultra-high strength martensite steel strongly depend on the shape, size and content of the reversed austenite. In general, the plasticity and toughness of the materials can be improved effectively by increasing the content of the reversed austenite. After aging treatment of Cu-bearing as-quenched steel with martensitic microstructure, Cu particles precipitate at the boundary of martensitic structure and act as heterogeneous nucleation sites to promote the nucleation of reversed austenite. In order to explore the effects of different alloying elements on heterogeneous nucleation of reversed austenite on Cu particles, the effects of <i>X</i> (<i>X</i> = Cr, Al, Mo, W, Ni, Co, Mn) on the interfacial properties of Cu/<i>γ</i>-Fe are studied via first-principles method. The adhesion work, interfacial energy and electronic structure of the interfaces before and after the replacement of Cu and Fe atoms at Cu/<i>γ</i>-Fe boundaries are calculated. The results show that when the alloying elements replace Cu atoms at the Cu/<i>γ</i>-Fe interface, strong <i>X</i>—Fe covalent bond forms at the Cu/<i>γ</i>-Fe interface, the adhesion work increases and the interfacial energy decreases, and thus improve the heterogeneous nucleation capability of reverted <i>γ</i>-Fe on Cu particles. When Fe atoms at the interface are replaced, the stability of the interface changes little, and the bonding between the doped atoms and the neighboring atoms is weak.

A Review of the Latest Developments in the Field of Refractory High-Entropy Alloys

This review paper provides insight into current developments in refractory high-entropy alloys (RHEAs) based on previous and currently available literature. High-temperature strength, high-temperature oxidation resistance, and corrosion resistance properties make RHEAs unique and stand out from other materials. RHEAs mainly contain refractory elements like W, Ta, Mo, Zr, Hf, V, and Nb (each in the 5–35 at% range), and some low melting elements like Al and Cr at less than 5 at%, which were already developed and in use for the past two decades. These alloys show promise in replacing Ni-based superalloys. In this paper, various manufacturing processes like casting, powder metallurgy, metal forming, thin-film, and coating, as well as the effect of different alloying elements on the microstructure, phase formation, mechanical properties and strengthening mechanism, oxidation resistance, and corrosion resistance, of RHEAs are reviewed.

Influence of Alloying Elements on the Dynamic Recrystallization of 4 wt.-% Medium Manganese Steels.

The hot deformation behaviour of air-hardening martensitic forging steels (of type 1.5132) is presented. The newly developed steels are characterized through dilatometric tests as well as through microstructure analyses with LOM and SEM and hardness measurements. Additionally, the influence of alloying elements on the flow curves at high temperatures is discussed. It is demonstrated that the higher alloying content does not increase the equivalent stresses in comparison to the reference alloys and contrariwise reduces the offset for dynamic recrystallization at temperatures below 1100 . Furthermore, the effect of different alloying elements on the strain hardening behaviour during hot compression of 4 medium manganese steels is presented. It is shown that boron reduces the offset for dynamic recrystallization if present in solid solution, while the combined addition of titanium and niobium annihilates the solid drag effect on the prior austenite grain boundaries.

Effects of different alloying elements M (M = Fe, Ni, Mn, Si, Mo, Cu, Y) on Cr2O3 with Cl: a first-principles study

Using the first-principles methods, the effects of different alloying elements M (M = Fe, Ni, Mn, Si, Mo, Cu, Y) on Cr2O3 with Cl adsorption are studied. The results show that the layer distance of all doped models has been widened to different degrees with Cl adsorption. When Mo or Y is doped into the passive film, the difference of layer distance is reduced to a certain extent. The interaction between alloying elements and Cl is studied by calculating the adsorption height, bond population and electron density difference. The results show that Mo and Y can inhibit Cl erosion and improve the corrosion resistance of passive film. Furthermore, we investigate the CrMoFe and CrMoY co-doped system with Cl adsorption. The calculations point out that when Mo and Y are doped together in the passive film, the corrosion resistance of the system is more prominent than that of CrMo, CrY and CrMoFe co-doping systems.

Influence of Cu, Zn and Si alloying elements on Al alloy foams produced using Mg blowing agent

The main focus of the present study is to compare the effect of different alloying elements on Al–Mg alloy foams. Al–Mg15–X10 (X = Cu, Zn and Si) alloy foams were produced via powder metallurgy route by using Mg as a blowing agent. Macro- and microstructural characterisations of the foams were performed using X-ray tomography, X-ray diffraction and scanning electron microscope. Corrosion studies such as weight loss measurement, hydrogen evolution method and potentiodynamic test were conducted. Mechanical properties were evaluated by subjecting the samples to quasi-static compression and microhardness tests. All the alloy foams showed a comparable structure. The Cu-containing foams exhibited the highest strength, while the Zn-containing foams showed the highest expansion. However, the other properties such as brittleness, elastic modulus and burning nature were found to be better for the Si-containing foams.

Effects of different alloying additives X (X = Fe, Ni, Mn, Co, Si, Nb, W, Cu, Ce, Y) and water on the structural of Cr2O3 film: a first-principles study

This study investigates the potential effects of different alloying elements X (X = Fe, Ni, Mn, Co, Si, Nb, W, Cu, Ce, Y) in the Cr2O3 (0001) layers with water adsorption by using the first-principles method. For water adsorption, the most stable adsorption site is bridge site. By calculating the adsorption energy of the alloy element doped layer, the distances of top Cr and O layer and charge densities of Cr and O atoms, it is concluded that the vapor corrosion resistance of the oxide film was improved after doping with elements such as Fe, Ni, Mn, Co, Si, Cu, Ce and Y. In particular, the rare elements doped system can obviously enhance resistance to water vapor erosion. By adding YCo and YW, the oxidation film showed better corrosion resistance than single-element doping and CoW co-doping systems.

Development of continuously cooled low-carbon, low-alloy, high strength carbide-free bainitic rail steels

In the present work, attempts have been made to design and develop low-carbon, low-alloy, high strength carbide-free bainitic steels for application in heavy-haul rail tracks. The study starts with an analytical approach for understanding the effects of different alloying elements on the thermodynamic and kinetic aspects of bainite transformation and the resultant microstructure and mechanical properties. Based on the analysis, two steel compositions were designed for further investigation. The alloys were prepared by melting and casting and processed by hot-rolling and air cooling, which is the usual route for the industrial production of rail sections. Microstructures of the developed steels primarily consisted of plates of carbide-free bainitic ferrite, interspersed with fine films of retained austenite. These continuously cooled steels offer ultra-high strength levels with very good ductility which are far superior to existing pearlitic grade rail steels. Detailed characterization and quantification of microstructural constituents have been carried out and they are correlated with the tensile proprieties using semi-empirical formulations available in literature.

Spark plasma sintering of low modulus titanium-niobium-tantalum-zirconium (TNTZ) alloy for biomedical applications

In metallurgy, titanium has been a staple for biomedical purposes. Its slow toxicity and alloying versatility make it an attractive choice for medical applications. However, studies have shown the difference in elastic modulus between titanium alloys (116 GPa) and human bone (10–40 GPa), which contributes to long term issues with loose hardware fixation. Additionally, long term studies have shown elements such as vanadium and aluminum, which are commonly used in Ti-6Al-4V biomedical alloys, have been linked to neurodegenerative diseases like Alzheimer and Parkinson. Alternative metals known to be less toxic are being explored as replacements for alloying elements in titanium alloys. This study will focus on advanced processing and characterization of β-phase titanium alloys for biomedical applications. The microstructure, mechanical, and electrochemical properties of these alloys have been analyzed and compared with C.P. titanium. Bond order B¯O and energy level M¯D approach has been used to design these alloys in order to achieve low elastic modulus. The main objective is to study the effect of different alloying elements on microstructure, phase transformation and mechanical properties of these newly developed low modulus β-phase titanium alloys and establish new avenues for the future development of biocompatible titanium alloys with optimum microstructure and properties.

Composition dependent microstructure evolution, activation and de-/hydrogenation properties of Mg–Ni–La alloys

In this work, in order to elucidate the effect of different alloying elements on the microstructure, activation and the de-/hydrogenation kinetics performance, the Mg–20La, Mg–20Ni and Mg–10Ni–10La (wt.%) alloys have been prepared by near equilibrium solidification combined with high-energy ball milling treatment to realize the internal optimization as well as particle refinement. The results show that the microstructures of the prepared alloys are significantly refined by forming different types and sizes of intermetallic compounds. Meanwhile, the effects of LaH3 and Mg2Ni within the activated samples on de-/hydrogenation kinetics are also discussed. It is observed that the alloy containing LaH3 preserves stable hydrogenation behavior between 573 and 623 K, while the hydrogenation properties of the alloy containing Mg2Ni is susceptible to temperature. A preferable hydrogenation performance is observed in Mg–10Ni–10La alloy, which can absorb as high as 5.86 wt% hydrogen within 15 min at 623 K and 3.0 MPa hydrogen pressure. Moreover, the desorption kinetics and the desorption activation energies are evaluated to illustrate the mechanism based on improved dehydrogenation performance. The addition of proper alloying elements Ni and La in combination with reasonable processing is an effective strategy to improve the de-/hydrogenation performance of Mg-based alloys.

Hydrolytic Hydrogen Production on Al⁻Sn⁻Zn Alloys Processed by High-Pressure Torsion.

Aluminium-tin-based alloys with different compositions were synthesized by a high-pressure torsion (HPT) method. The effect of different alloying elements and processing routes on the hydrogen generation performance of the alloys was investigated. The results show that Zn can enhance the hydrogen generation rate and yield by promoting pitting corrosion. The highest reactivity in water was achieved for an Al-30wt %Sn-10wt %Zn alloy. Detailed analysis of the Al-30wt %Sn-10wt %Zn alloy shows that increasing the shear strain and the resultant formation of ultrafine grains and phase mixing enhance the hydrogen generation rate through the effects of both nanogalvanic cells and pitting corrosion.

The action mechanism and application of alloying elements in the pressure vessel steel

The research progress of the influence of alloying elements on the microstructure and mechanical properties of pressure vessel steel was summarized. The effects of different alloying elements on the composite mechanical properties of the pressure vessel, such as the strength and toughness and the low temperature fracture resistance, were analysed. The action mechanism of alloying elements in pressure vessel steel was generalized. Combined with the actual production, the adding alloying elements, the research progress and the development prospect of the nuclear power pressure vessel steel were mainly analysed and discussed. The future research should focus on the mechanism of each component element, clarify the interaction relationship between the alloying elements, and develop a complete set of alloy adding scheme. So that the pressure vessel steel, which not only conforms to the actual situation, but also meet the specific requirements should be produced.

GG25 GRİ DÖKME DEMİR MALZEMESİNİN ÜRETİMİNDE BULANIK İSTATİSTİKSEL PROSES KONTROLÜNÜN UYGULANMASI

The group of ferrous materials with more than 2% carbon in their chemical composition is commonly referred to as cast iron materials. Carbon Equivalent (CE) is an empirical value in weight percent, relating the combined effects of different alloying elements used in the making of cast iron to an equivalent amount of carbon. Statistical process control (SPC) can be applied in plants to obtain good quality and high standard products which have become very popular in many industries. Fuzzy process capability analysis by using X-R control charts gives more realistic results, developed with fuzzy theory. Fuzzy control charts are more sensitive than SPC. This study contains construction of a system design to observe whether the conditions of an alloy production line are within the specification and control limits. To determine the average percentage of CE values, the fuzzy X-bar and R charts were applied to GG25 gray cast iron samples for 20 days’ production. In order to control the process parameters and improve quality of the cast products, the comparison of the statistical and experimental results show that the fuzzy SPC methods can be simply applied on a foundry. Keywords: GG25 gray cast iron, carbon equivalent, fuzzy statistical process control

Recent research and developments on wrought magnesium alloys

Abstract Wrought magnesium alloys attract special interests as lightweight structural material due to their homogeneous microstructure and enhanced mechanical properties compared to as-cast alloys. In this contribution, recent research and developments on wrought magnesium alloys are reviewed from the viewpoint of the alloy design, focusing on Mg-Al, Mg-Zn and Mg-rare earth (RE) systems. The effects of different alloying elements on the microstructure and mechanical properties are described considering their strengthening mechanisms, e.g. grain refinement, precipitation and texture hardening effect. Finally, the new alloy design and also the future research of wrought magnesium alloys to improve their mechanical properties are discussed.

Investigation of the surface of antifriction Al–Cu–Si–Sn–Pb aluminum alloys

The tribological and mechanical properties of Al–Cu–Si–Sn–Pb alloys are studied. The effect of different alloying elements on the structure of their surface and its tribological properties is estimated. The alloys are studied at different stages of their production, i.e., after casting and homogenizing annealing. The character of surface transformations under friction simulated on fiction machines is investigated. The surface is visualized by means of optical and scanning probe microscopy and scanning electron microscopy combined with elemental analysis. Great amounts of oxygen leading to the formation of oxide particles with abrasive properties are revealed on the contact surfaces. The mass transfer of chemical elements also occurs in the contact area: the material of an insert “spreads” over the shaft to form a film of secondary structures. At small thicknesses, this film serves as a solid lubricant, but might promote the formation of scoring during the development of microrelief. The application of two hardness measurement methods, such as “microindentation” and “nanoindentation”, give mutually complementary results. The highest mechanical properties (hardness, up to 0.5 GPa) are established to be attained in silicon- and copper-containing alloys. Homogenizing annealing at 400°C is also revealed to decrease the hardness, but improve the plasticity, which is important for antifriction materials.