Arc Melting Furnace Research Articles

Effects on Microstructure and Material Properties for TiNiCo Shape Memory Alloy

Wire spark discharge machining of TiNiCo alloys for bone staple applications is presented. A vacuum arc melting furnace was used to develop TiNiCo alloys with varied cobalt (Co) contents (1, 5 and ...

Electrochemical Behaviour of Ti-Mo Alloys for Medical Application in Biological Solution

Nowadays, primordial concern represent population health with all materials that are used in medical applications. It were obtained three alloys of titanium with addition of elements like molybdenum, zirconium and tantalum, in a vacuum arc melting furnace (VAR), in argon atmosphere. These alloys were investigated in biological solution, similar with to the human body by electrochemical study method (linear and cyclic polarization). Results revealed that it possesses a good behaviour which does not influence the human body, with future applications in medical field.

Dynamic behavior and microstructure characterization of TaNbHfZrTi high-entropy alloy at a wide range of strain rates and temperatures

The TaNbHfZrTi refractory high-entropy alloy (RHEA) is suction casted by vacuum arc melting furnace. The mechanical behavior of the TaNbHfZrTi RHEA is systematically investigated through material testing machine and Split Hopkinson Pressure Bar (SHPB) system at strain rate up to 2600s-1 and temperatures from 77K to 873K. Significant increases in the yield strength and interesting changes in strain rate sensitivity at high strain rates and high temperatures are observed. During the dynamic tests, the strain rate sensitivity rises from ~5 to ~76 with the temperature increases from 293K to 673K, demonstrating that high temperature has a significant influence on the strain rate effect of the TaNbHfZrTi RHEA. The comprehensive analysis of electron backscatter diffraction (EBSD) and Kernel Average Misorientation (KAM) technique shows that the pronounced homogeneous deformation microstructures exist in the sample even at the true strain of about 0.34, only very short adiabatic shear band (ASB) initiates. The fracture morphology investigated by scanning electron microscopy (SEM) indicates both ductile and brittle fracture behavior of the TaNbHfZrTi RHEA at 77K. The improved Johnson-Cook (J-C) model is proposed to describe the deformation behavior, in which both strain rate hardening and temperature softening terms are expressed as a function of strain and strain rate, respectively.

Influence of Fe on Microstructure and Physical Properties of Cu90 – xFexPd10 Ternary Alloys with x = 5, 10, 15, and 20

The structural and physical properties of Cu90 – xFexPd10 ternary alloys with x = 5, 10, 15, and 20 are studied using X-ray diffraction, resistivity measurements, Vickers hardness tester, and tensile testing machine. The samples were prepared by using arc-melting furnace under an atmosphere of purified Argon. The integrated intensity data obtained from X-ray diffraction are used to determine microstructure and hence lattice parameter. The lattice parameter has shown a negative deviation from Vegard’s rule. The addition of Fe in Cu90 – xFexPd10 alloy improves the structure, and increases the electrical resistivity and the hardness of alloy. With the addition of Fe, the mechanical properties of alloy such as ultimate tensile strength, Young’s modulus, and elongation are decreasing, while the elastic limit is increasing.

Study on Microstructure and Corrosion Resistance of AlCoCrFeNiTi(x) High-Entropy Alloys

AlCoCrFeNiTi(x) (x=0, 0.4, 0.8, 1.0) high entropy alloys (HEAs) were prepared by vacuum arc melting furnace. The results showed that AlCoCrFeNiTi(x) HEAs transformed from a single body-centered cubic structure (BCC) to two kinds of body-centered cubic structures accompanied by a small amount of Laves phase with the increase of Ti content, and the morphology of alloy structure changed from dendrites to the petal-like equi-axed crystals. In addition, the alloy with the content of 0.4 mol. % Ti has a corrosion potential of -0.335V and a minimum corrosion current density of 7.36×10−7 A/cm2, which indicated that the HEAs with the content of 0.4 mol.% Ti has the best corrosion resistance.

The effect of TiC addition on the microstructure and mechanical properties of Al0.6CrFe2Ni2 high entropy alloys

To enhance the strength of single FCC phase high entropy alloys, TiC was selected as reinforced phase to improve the properties of high entropy alloys (HEAs). Therefore, a series of TiC/Al0.6CrFe2Ni2 high entropy alloys with different TiC content which ranging from 0 to 5 vol% were prepared by vacuum arc melting furnace. The phase compositions, microstructures and mechanical properties of alloys were investigated detailedly. The results show that TiC has no effect on phase composition of the alloys, but the addition of ceramic phase TiC has an advantageous effect on the mechanical properties of alloys, the yield strength of TiC/Al0.6CrFe2Ni2 HEAs increases due to the refined of grain size, when TiC content is 2.50 vol%, alloy has better properties, the yield strength and Vickers hardness are 576.93 MPa and 244 HV, respectively.

Rapidly solidified Sm-Co-Hf-B magnetic Nano-composites: Experimental and DFT studies

The effect of Hf and B additions on the phase stability, microstructure and magnetic properties of the metastable SmCo7 (1:7H) ribbons has been investigated with a combined approach of experimental measurements and first principle DFT (density functional theory) calculations. A series of (Sm0.12Co0.88)95Hf5−xBx (x = 0, 1, 2, 3, 4 and 5) alloys were arc-melted in a TIG (tungsten inert gas) arc melting furnace, followed by melt-spinning onto a copper roller at a wheel velocity of 40 m/s. Characterization based on X-ray diffraction indicates that the major phase is SmCo7 having meta-stable (TbCu7-type) structure. From the total energy calculations using DFT, the phase stability of (Sm0.12Co0.88)95Hf5−xBx ribbons have been confirmed. Moreover, Hf and B addition results in an effective grain refinement; average grain size being as low as ~ 80 nm. The reduction in grain size leads to significant changes (increase or decrease) in magnetic properties depending on the Hf/B ratio. The coercivity value (Hc) varies between 7 kOe and 12 kOe as x (at.% B) increases from 0 to 5 at.%. The experimental coercivity values have been compared with the computed anisotropy energies. The saturation magnetization (Ms) increases from ~ 54 emu/g to 77 emu/g with increasing B concentration (x).

Nanoporous layer formation on the Ti10Mo8Nb alloy surface using anodic oxidation

Beta titanium alloys with a low elastic modulus, such as Ti10Mo8Nb alloy, are suitable to relieve the stress shielding effect that occurs in the interface implant/bone. However, these materials are considered bioinert and changing the surface topography is necessary to improve cell adhesion and, consequently, osseointegration. The purpose of this research is the surface modification of Ti10Mo8Nb experimental alloy using anodic oxidation. Ingots of Ti10Mo8Nb experimental alloy were produced by melting in arc melting furnace, cold worked and heat treatment. The anodic oxidation was performed to change the alloy surface using an organic electrolyte under 20 V for 10.8 ks at room temperature. The Ti10Mo8Nb alloy exhibited a beta phase and after the surface treatment, a hydrophilic nanoporous layer of TiO2 was obtained. The anatase phase was observed in the annealed samples around 400 °C without deterioration of this nanostructure. Under these conditions, the sample there was a tendency to improve cellular behavior on the material surface due to their hydrophilic behavior as compared to the sample without surface treatment and the nanoporous layer in the amorphous state. In this sense, the adequate bulk properties together suitable surface response makes Ti10Mo8Nb alloy attractive for biomedical applications.

AISI 316 L Paslanmaz Çelik ile Fe60Al40 Metaller arası Bileşiğin Sürtünme Kaynağı ile Birleştirilmesi

In this study, the bonding of AISI 316L stainless steel and FeAl based intermetallic compound with friction welding was investigated. The FeAl intermetallic compound was produced in a vacuum arc melting furnace, while AISI 316L stainless steel was supplied from the market. The friction welding process was carried out at a friction speed of 1000 rpm, under a friction pressure of 150 MPa, for friction times of 6, 9 and 12 seconds. The strength of the welding interface was measured by shear test. The highest strength value was found to be as 281 MPa in the sample welded for 12 seconds. The hardness deviation in the welding zone was determined by micro hardness measurement from one material to another one. The welding interface was examined by Scanning Electron Microscopy (SEM) and the composition analysis along a line in the welding region showed that the amount of alloying elements changed. This revealed that the elements of both materials are diffused each other at the welding interface.

Preparation, structural, microstructural, mechanical and cytotoxic characterization of as-cast Ti-25Ta-Zr alloys.

Titanium alloys have been widely used as biomaterials, especially for orthopedic prostheses and dental implants, but these materials have Young's modulus almost three times greater than human cortical bones. Because of this, new alloys are being produced for the propose of decreasing Young's modulus to achieve a more balanced mechanical compatibility with the bone. In this paper, it is reported the development of Ti-25Ta alloys as a base material, in which was introduced zirconium, with concentration varying between 0 and 40 wt%, with the aim of biomedical applications. The alloys were prepared in an arc-melting furnace. The microstructural analysis was performed by x-ray diffraction as well as optical and scanning electron microscopy. Selected mechanical properties were analyzed by microhardness and Young's modulus measurements, and cytotoxicity analysis by indirect test. X-ray measurements revealed the presence of α″ phase in the alloy without zirconium; α″ + β phases for alloys with 10, 20, and 30 wt% of zirconium, and β phase only for the alloy with 40 wt% of zirconium. These results were corroborated by the microscopy results. The hardness of the alloy was higher than that of cp-Ti due to the actions of zirconium and tantalum as hardening agents. The Young's modulus decreases with high levels of zirconium due to the stabilization of the β phase. The cytotoxicity test showed that the extracts of studied alloys are not cytotoxic for osteoblast cells in short periods of culture.

Effect of Thermo-mechanical Treatment on Microstructure and Mechanical Properties of Two-phase TiNbO Alloy

We designed the composition of alloy with Ti-8Nb-0.5O (at. %) and fabricated in high vacuum arc-melting furnace. This work was focused on the effect of thermomechanical treatment on microstructure and mechanical properties. Transmission Electron Microscope (TEM), Scanning Electron Microscope (SEM), X-ray Diffraction analysis (XRD), Micro Vickers Hardness Tests and Tensile Tests were utilized to characterize the alloys. The annealing temperature has a significant effect on the microstructure and mechanical properties of TiNbO alloy. When the alloy was annealed at 300℃, 400℃ or at hot-rolled state, there were just α and β phases in the alloy. When the alloy was annealed at 500℃, 600℃, the alloy recrystallized and harmful ω phase appeared, which increased the modulus and strength of the alloy greatly. When the alloy is annealed at 700℃, the alloy recrystallized completely without ω phase. When we accelerated the cooling rate after annealed, the martensitic transformation appeared, which restrained the appearance of ω phase and reduced the modulus.

Using thermochemical treatment for facilitating apatite formation on Ti-Nb-Sn alloys

Titanium alloys are promising candidates for biomedical applications, and alloys based on the Ti-rich side of Ti-Nb-Sn system have presented material properties deserved for orthopedic implant applications. However, to our knowledge, the structural studies related to surface of these alloys are limited. Ti-18Nb-11Sn and Ti-35Nb-4Sn alloys were synthesized, and the influence of thermochemical treatment on the bioactivity was investigated. The alloys were synthesized by arc melting furnace and then were submitted to thermochemical treatment. X-ray diffraction and scanning electron micrograph analysis showed high crystallinity and maintenance of microstructure of the both alloys before and after thermochemical treatment. The results indicated that the Ti-18Nb-11Sn alloy was not demonstrated to be bioactive, while the Ti-35Nb-4Sn alloy slightly presented bioactivity, which increased after the thermochemical treatment. Meanwhile, the Ti-18Nb-11Sn alloy presented a low hardness value, making it not compatible with biomedical applications. However, the Ti-35Nb-4Sn alloy presented an acceptable hardness value for biomedical applications. We believe that the results reported herein suggest that the Ti-35Nb-4Sn alloy may be attractive for designing biomedical devices with improved performances toward the adhesion of apatite.

Corrosion Behavior of Fe-7Cr-1Mo-12Zr Metal Waste Form Alloy in Simulated Repository Environment

Metal waste forms (MWF) are solid metallic waste categorized as high-level radioactive waste generated during pyro-reprocessing of spent metallic fuels and geologically disposed off. This waste form generated requires an excellent corrosion resistance in a geological repository environment. In the present work, Fe-7Cr-1Mo-12Zr MWF alloy was developed by casting in an arc melting furnace. The x-ray diffraction analysis revealed the formation of stable phases of α-Fe solid solution and the intermetallic phases of Fe2Zr and Fe23Zr6. The corrosion behavior of Fe-7Cr-1Mo-12Zr alloy was investigated using electrochemical techniques in aggressive (highly acidic with Cl−) and nominal repository pH environment. Cyclic potentiodynamic polarization studies indicated the shift in corrosion potential toward cathodic potential in highly acidic solution with Cl−. The corrosion mechanism of pitting is associated with acidified pH medium with more Cl−, whereas uniform corrosion or transpassive dissolution is resultant of mild acidity or mild alkaline medium. The passive region is wider in pH 5 and 8 when compared to pH 1 and 3. Electrochemical impedance spectroscopic (EIS) analysis revealed the lowering of passive film stability in the highly acidic medium in the presence of Cl−. The role of passive oxide layers on the corrosion resistance of the Fe-7Cr-1Mo-12Zr MWF alloy is discussed.

Effect of partial substitution of In with Mn on the structural, magnetic, and magnetocaloric properties of Ni2Mn1+xIn1−x Heusler alloys

The structural, magnetic and magnetocaloric properties of Ni2Mn1+xIn1−x alloys, prepared using an arc-melting furnace in an argon environment, have been studied for their potential application in cost-effective magnetic refrigeration technology. The room-temperature x-ray diffraction shows that the Ni2Mn1+xIn1−x alloys with 0 ⩽ x ⩽ 0.34 exhibit austenite cubic phase, whereas the alloys with x > 0.34 have mixed tetragonal martensite and cubic austenite phases. The Ni2Mn1.34In0.66 alloy shows a clear second-order phase transition with a Curie temperature of 305 K but its elemental composition is very close to the critical composition between first and second–order phase transitions. The calculated magnetic entropy change and relative cooling power of the Ni2Mn1.34In0.66 alloy measured at 3 T field are 4.5 J kg−1 K−1 and 201 J kg−1, respectively. The temperature dependent resistivity of Ni2Mn1.34In0.66 alloy measured at H = 0 Oe shows that the sample has a room temperature resistivity of 7 The absence of thermal and magnetic hysteresis due to second-order magnetic phase change, coupled with higher values of magnetic entropy change and relative cooling power, suggests that the Ni2Mn1.34In0.66 alloy has the potential for magnetic refrigeration.

Electric Arc Vacuum Technologies and the Related Equipment

The following results of studying electric discharges over a wide pressure range and designing technological equipment based on these results and performed in Bauman Moscow State Technical University are presented: a magnetically controlled argon torch for welding, soldering, and heat treatment; a small electric arc melting furnace; and technology and equipment for the cleaning of metallic articles from contaminations and for reaching the required surface roughness according to a functional purpose.

Effects of nano-Y2O3 addition on the microstructure evolution and tensile properties of a near-α titanium alloy

Reactive element oxide (REO) can significantly refine cast microstructure and improve mechanical properties. In this study, Y2O3 nanoparticles (∼30 nm) were added into a near-α titanium alloy by vacuum arc melting furnace. The nano-Y2O3 grew into dendritic and near-equiaxed Y2O3 crystals because of segregation in the solution. Apart from refined β grain size, Y2O3 particles also coarsened the needle α lamellar (αs) by providing supernumerary nucleation sites for αs in subsequent β→αs transformation. Owing to the load transfer mechanisms, ultimate tensile strength and yield strength were evidently enhanced either at room or elevated temperature. The theoretical strengthening model of Y2O3/near-α-Ti alloy matched the experimental values well.

Refinement mechanism and physical properties of arc melted invar alloy with different modifiers

Abstract Strengthening invar alloy while ensuring its low coefficient of thermal expansion by refining microstructure has been a thorny issue in recent years. In the present work, the effects of Ti, Nb and Ti-Nb compound modifier on rapid solidified microstructure and properties of invar alloy prepared by a mini-type vacuum arc melting furnace were investigated in detail. Invar alloy with uniform and fine structure was obtained by adding 0.2%Ti, 0.2%Nb or 0.2%Ti-Nb compound modifier. And the formation of cellular substructure is attributed to the supercooling condition, leading to segregation of Ni element at the cellular wall and high dislocation density at the intracellular. Results showed that Ti-Nb has the most remarkable refinement and strengthening effect compared with Ti and Nb, who can make the refinement rate of austenite grain and substructure of invar alloy up to 45% and 67.4%, respectively. Moreover, it is revealed that the coefficient of thermal expansion (CTE) of invar alloy with the addition of alloying elements is decreased, which is mainly due to lattice distortion. In addition, the addition of alloying elements is beneficial to the dislocation multiplication of the invar alloy leading the increase of dislocation density, especially for invar alloy with the addition of 0.2%Ti-Nb modifier.

Effect of Small Additions of Cr, Ti, and Mn on the Microstructure and Hardness of Al–Si–Fe–X Alloys

The Al–Si–Fe system has drawn the attention of the scientific community due to its capacity to replace parts in several manufacturing industries, as this alloy system is very sensitive to small additions of transition metals. Therefore, the aim of this work is to study the effect of Cr, Ti, and Mn additions in the Al–20Si–5Fe (wt. %) alloy and to study the modification of the iron intermetallic and the microstructural refinement through the formation of secondary phases. Al–20Si–5Fe–X (X = Cr, Mn and Ti at 1.0, 3.0, and 5.0 wt. %) alloy ingots were prepared by arc melting furnace. The elemental chemical analysis was performed by X-ray fluorescence spectrometry (XRF). The microstructure of all samples was investigated by scanning electron microscopy and X-ray diffraction. Finally, microhardness was measured in order correlate the hardness with the formation of the different compounds. The highest hardness was found for the alloy with the 5 wt. % Cr. The addition of Ti and Mn raised the hardness by ~35 HVN (Vickers microhardness) when compared to that of AlSiFe master alloy. Important changes were also observed in the microstructure. Depending on the Cr, Ti, and Mn additions, the resulting microstructure was dendritic (CrFe), acicular (Ti5Si3), and “bone like” (Mn0.2Fe0.8), respectively.

Mg-based Nanocomposites for hydrogen storage containing La23Nd8.5Ti1.1Ni33.9Co32.9Al0.65 alloys as additives

Abstract Mg based nanocomposites containing different concentrations of La23Nd8.5Ti1.1Ni33.9Co32.9Al0.65 alloy has been undertaken at present work. Doped alloy was prepared by arc melting furnace and ball milled to get its nano structured. Hydrogen sorption properties of MgH2+ x wt% (x=10, 25 and 50) La23Nd8.5Ti1.1Ni33.9Co32.9Al0.65 alloy was characterized for their thermal, morphological and structural properties. Result shows that the alloy significantly reduced onset temperature of desorption. The TGA analysis showed higher desorption temperature for milled MgH2 compared to x wt% alloy added MgH2. Furthermore, the estimated activation energy for hydrogen desorption was found to be -177.90 , -204.65, -79.15 and -185.29 kJ/mol for milled ,10 wt%, 25 wt% and 50 wt % MgH2 respectively and also shows the reduction of activation energy by 98 kJ/mol due to the addition of 25 wt% alloy additives resulted the improved hydrogen storage capacity. The phase and purity of MgH2 during milling was studied by XRD and it is revealed that maximum stable and improved phase alteration for Hydrogen sorption was obtained during 25 wt % alloy milling. Morphological studies by SEM were undertaken to investigate the effect of hydrogenation of nanostructured alloy. DSC investigations were carried out to investigate the effect of alloy on hydrogen absorption behaviour of MgH2.

Use of periclase-carbon lining in DC arc melting furnaces during processing of secondary raw materials

The experience of operating a DC arc furnace in JSC "Krastsvetmet" for recycling of secondary raw materials using periclase-carbon products as a working layer of lining is presented. A comparative analysis of the operation of a DC arc furnace with periclase and periclase-carbon lining is described.Ill.2.