Arc Casting Research Articles

Increasing ductility via Cu addition in AlxCrFeMnNi: Towards a scrap-based high entropy alloy

Alloys comprising common alloying elements are more amenable to accepting high fractions of scrap. The present study examines the effect of Cu and Al addition on common element containing multiple principal element alloy (CE-MPEA): AlxCuyCrFeMnNi (x = 0, 0.15, 0.3, 0.6, 0.9 and y = 0, 0.07, 0 = 0.14). Alloys were fabricated by arc casting. As expected, after quenching, the microstructures displayed FCC A1, Cr-rich BCC A2 and B2 precipitate phases in varying amounts. Adding small amounts of Cu to low and medium Al alloy groups increased the FCC phase fraction and refined the FCC grains. It is proposed that these microstructural changes account for the increased ductility seen to accompany Cu addition. A hybrid model was successfully employed to predict the hardness of the FCC phase. In contrast to high Cu-containing HEAs from prior studies, Cu additions in the studied alloys did not detrimentally affect the corrosion resistance in idealised polarization corrosion tests in salt solution. This can be ascribed to the absence of a Cu-rich FCC phase at the low Cu levels employed in the present work. The current alloys show promise as a base composition for further development into a tough fine-grained stainless alloy able to be produced using high fractions of scrap input.

Effect of Zr content on the physicochemical, electrochemical, and biological properties of Ti80Nb20-based alloys

The β-Ti alloys have become very attractive in the area of biomedical materials due to their corrosion resistance, biocompatibility, and low elastic modulus as compared with other materials. In this context, the Ti-Nb-Zr ternary system has gained more interest because Zr acts as secondary β-Ti stabilizing element when it is added together with β-stabilizing element such as Nb or Mo. According to the d-electron theory, the higher the Zr content, the lower elastic modulus values are obtained, which would allow to produce alloys with low elastic modulus, corrosion resistance, and shape memory. However, determining the ideal amount of Zr in a Ti-Nb-Zr alloy is still a matter of investigation. In this work, alloys with a nominal chemical composition of Ti80−x-Nb20-Zrx (x = 5, 10, 20, 30, and 40 at%) were produced by electric arc casting. The results show that the addition of Zr causes a decrease in both the elastic modulus and the hardness of the molten alloys, reaching values of 50.5 GPa for a sample with 40 at% Zr. The increase in the Zr content caused a microstructural difference between the phases, and the α” phase was detected for the Ti80Nb20, Ti75Nb20Zr5, and Ti60Nb20Zr20 alloys. The X-ray photoelectron spectroscopy (XPS) analysis revealed that the environment influences the Ti-Nb-Zr surfaces, showing the growth of oxide layers, mainly Ti, Zr and, to a lesser extent, Nb oxides. All alloys with different Zr amounts showed wide passivation regions and no sign of pitting in the potential range that is characteristic of the human body. The Ti-Nb-Zr alloys showed good compatibility in cell growth tests, with the best results for the 20 at% Zr alloy, and a decrease in biocompatibility for higher Zr amounts due to reactions of Zr4+ with body fluids.

Fabrication of titanium restoration by means of calcium aluminate-bonded magnesia investment material and one-chamber arc casting apparatus.

Cast titanium restoration for molars has high biocompatibility and is covered by the Japanese national health insurance. Titanium casting requires specific investment material and casting apparatus. A cast restoration for the mandibular left second molar was fabricated using titanium in this study. A wax pattern fabricated on a definitive cast was invested in calcium aluminate-bonded magnesia investment material. Titanium was cast using an argon gas pressure one-chamber casting apparatus. No defects were observed on the surface and the hole was clearly reproduced. A smooth surface on the restoration was obtained by polishing at low speed. Reproductivity and polishing properties of the titanium restoration fabricated in this study were comparable to those of conventional dental metal restorations.

Effect of the microstructure refinement by powder metallurgy on the oxidation behavior of Nb-6Mo-20Si-3Cr silicide-based alloy

This study investigated the effect of the microstructure refinement on the oxidation resistance of the Nb-6Mo-20Si-3Cr silicide-based alloy based on how the oxidation behavior of the alloy is severely affected by its microstructure size. Alloy powders were fabricated by a hydrogenation-dehydrogenation method, and were consolidated by a spark plasma sintering process. The sample, having a refined microstructure, could be fabricated by adopting a powder metallurgy method, and its microstructure is much finer than that of the sample fabricated by arc casting. To compare the oxidation resistance, the cast ingot and the sintered compact were oxidized at 1200 °C at various durations in an air atmosphere. The oxidation behavior of both followed the parabolic rate law. Based on the oxidation results, the parabolic rate constant of the cast ingot was 5.93 × 10−7 g2cm−4s−1, while, in the SPS compact, it was decreased to 2.31 × 10−7 g2cm−4s−1. By the microstructure and oxidation behavior results, this study confirms that the oxidation resistance of the Nb-6Mo-20Si-3Cr alloy could be improved by microstructure refinement.

In Situ Neutron Diffraction Study of Crystallographic Evolution and Thermal Expansion Coefficients in U-22.5 at.%Zr During Annealing

A uranium-22.5 at.%zirconium (U-10 wt.%Zr) ingot was manufactured by traditional arc casting. The sample was characterized by high-pressure preferred-orientation time-of-flight neutron diffractometry with in situ heating reaching 900°C. The phase transitions, lattice parameter ratios, and linear coefficients of thermal expansion were investigated experimentally. Contradictory to commonly referenced phase diagrams, the results of this work showed that the β-U+γ″-UZr dual-phase region is not present in U-22.5 at.%Zr. Rather, only two phase transformations were observed upon cooling. These transformations occurred at 655°C and 600°C and corresponded to γ-UZr → α-U+γ″-UZr → α-U+δ-UZr2, respectively. The linear coefficients of thermal expansion were measured for α-U, δ-UZr2, and γ-UZr. The thermal expansion of α-U was shown to be anisotropic in nature with significant lattice contraction in the 010b direction. Similar anisotropy albeit to a lesser extent was observed in δ-UZr2 with contraction in the 001c direction.

Effects of Solid Solution Strengthening Elements Mo, Re, Ru, and W on Transition Temperatures in Nickel-Based Superalloys with High \u03b3\u2032-Volume Fraction: Comparison of Experiment and CALPHAD Calculations

We prepared 41 different superalloy compositions by an arc melting, casting, and heat treatment process. Alloy solid solution strengthening elements were added in graded amounts, and we measured the solidus, liquidus, and γ′-solvus temperatures of the samples by DSC. The γ′-phase fraction increased as the W, Mo, and Re contents were increased, and W showed the most pronounced effect. Ru decreased the γ′-phase fraction. Melting temperatures (i.e., solidus and liquidus) were increased by addition of Re, W, and Ru (the effect increased in that order). Addition of Mo decreased the melting temperature. W was effective as a strengthening element because it acted as a solid solution strengthener and increased the fraction of fine γ′-precipitates, thus improving precipitation strengthening. Experimentally determined values were compared with calculated values based on the CALPHAD software tools Thermo-Calc (databases: TTNI8 and TCNI6) and MatCalc (database ME-NI). The ME-NI database, which was specially adapted to the present investigation, showed good agreement. TTNI8 also showed good results. The TCNI6 database is suitable for computational design of complex nickel-based superalloys. However, a large deviation remained between the experiment results and calculations based on this database. It also erroneously predicted γ′-phase separations and failed to describe the Ru-effect on transition temperatures.

Effects of minor Si on microstructures and room temperature fracture toughness of niobium solid solution alloys

Controlling the elements content in the niobium solid solution (NbSS) is significant for the better comprehensive performance of Nb-silicide-based alloys. In this paper, the effects of minor Si on the microstructures and room temperature fracture toughness of Nb–(0/0.5/1/2)Si–27.63Ti–12.92Cr–2.07Al–1.12Hf (at%, unless stated otherwise) solid solution alloys were investigated. The alloys were processed by vacuum arc-casting (AC), and then heat treated (HT) at 1425°C for 10h. In HT alloys, NbSS grains are refined gradually with the increase of Si content. Meanwhile, the volume fraction of Cr2Nb and silicides phases precipitates increases. The fracture toughness of HT alloys decreases at first but then increases in the range of 0 to 2% Si, because it is a combinatorial process of positive and negative effects caused by the addition of Si. The refinement of NbSS grains displays positive effect on fracture toughness, while the increase of solid solubility of Si in NbSS and brittle Cr2Nb and Nb-silicides precipitate phases display negative effect.

Sn 및 Cu를 첨가한 치과 주조용 Co-Cr-Mo계 합금제조 및 용해과정 분석

Purpose: Dental casting #Gr I (Co-25Cr-5Mo-3Sn-1Mn-1Si), #Gr II (Co-25Cr-5Mo-5Cu-1Mn -1Si) and #Gr III (Co-25Cr-5Mo-3Sn-5Cu-1Mn-1Si) master alloys of granule type were manufactured the same as manufacturing processes for dental casting Ni-Cr and Co-Cr-Mo based alloys of ingot type. These alloys were analyzed melting processes with heating time of high frequency induction centrifugal casting machine using infrared thermal image analyzer. Methods: These alloys were manufactured such as; alloy design, the first master alloy manufatured using vacuum arc casting machine, melting metal setting in crucible, melting in VIM, pouring in the mold of bar type, cutting the gate and runner bar and polishing. These alloys were put about 30g/charge in the ceramic crucible of high frequency induction centrifugal casting machine and heat, Infrared thermal image analyzer indicated alloys in the crucible were set and operated. Results: The melting temperatures of these alloys measuring infrared thermal image analyzer were decreased in comparison with remanium GM 800+, vera PDI, Biosil f, WISIL M type V, Ticonium 2000 alloys of ingot type and vera PDS(Aabadent, USA), Regalloy alloys of shot type. Conclusion: Co-Cr-Mo based alloy in addition to Sn(#Gr I alloy) were decreased the melting temperature with heating time of high frequency induction centrifugal casting machine using infrared thermal image analyzer.

Sliding Wear Behaviour of Cu-10Fe-3Ag <i>In Situ</i> Composite

A deformation-processed Cu-10Fe-3Ag in situ composite was made by consumable arc melting and casting followed by extensive deformation. A superior combination of mechanical strength and electrical/thermal conductivity was achieved with the composite since Fe filaments existed in the copper matrix. The effects of sliding speed and electrical current on sliding wear behavior and microstructure of the composite were investigated on wear tester. Worn surfaces of the Cu-10Fe-3Ag in situ composite were analyzed by scanning electron microscopy (SEM). Within the studied range of electrical current and sliding speed, the wear rate increased with the increasing electrical current and the sliding speed. Compared with Cu-10Fe in situ composite under the same conditions, the Cu-10Fe-3Ag in situ composite had much better wear resistance. Adhesive wear, abrasive wear and arc erosion were the dominant mechanisms during the electrical sliding processes.

Phase characteristics of a U–20Pu–3Am–2Np–15Zr metallic alloy containing rare earths

Metallic fuel alloys consisting of uranium, plutonium, and zirconium with minor additions of americium and neptunium are under evaluation for potential use to transmute long-lived transuranic actinide isotopes in fast reactors. The current irradiation test series design, designated AFC2, includes minor additions of rare earth elements to simulate expected fission product carry-over from the electrochemical molten salt reprocessing technique. The metal fuel alloys have been fabricated by an arc casting technique. The as-cast fuel alloys have been investigated for phase and thermal properties, specifically, enthalpies of transition, transition temperatures, and room temperature phase characteristics. Results and observations related to these characteristics for the “fresh” fuel alloys are provided. The alloy compositions are based on a U–20Pu–3Am–2Np–15Zr alloy, along with additions of 1 and 1.5 wt% RE (at the expense of U) where RE denotes rare earth alloy of cerium, lanthanum, praseodymium and neodymium. Phase behavior and associated transitions have been compared to available U–Pu–Zr ternary diagrams with acceptable agreement. Enthalpies of transition were deconvoluted from heating and cooling thermal traces for relatively reliable values. The rare earth additions to the base alloy have a minimal influence on the room temperature phases present, but the room temperature phases present slightly impacted the enthalpies of transition and transition temperatures.

Wear Performance of Mo3Si Alloys with Nb

Samples alloyed from zero up to 20 Nb at.% were produced by arc casting. Wear resistance is evaluated under dry sliding wear test conditions at different loads. Samples with a higher Nb at.% worn on an AISI 9840 steel disk had better resistance in comparison with samples without Nb reaching values up to 30%. This effect is explained considering the differences in oxidation between the substrate and the sample surfaces obtained by SEM analysis which explains the resistance improvement for the alloys with the Nb solid solution additions.

Interdiffusion in γ (face-centered cubic) Ni-Cr-X (X=Al, Si, Ge, or Pd) alloys at 900 °C

Interdiffusion in nickel (Ni)-chromium (Cr) (face-centered cubic γ phase) alloys with small additions of aluminum (Al), silicon (Si), germanium (Ge), or palladium (Pd) was investigated using solid-to-solid diffusion couples. Ni-Cr-X alloys having compositions of Ni-22at.% Cr, Ni-21at.%Cr-6.2at.%Al, Ni-22at.%Cr-4.0at.%Si, Ni-22at.%Cr-1.6at.%Ge, and Ni-22at.%Cr-1.6at.%Pd were manufactured by arc casting. The diffusion couples were assembled in an Invar steel jig, encapsulated in Ar after several hydrogen purges, and annealed at 900 °C in a three-zone tube furnace for 168 h. Experimental concentration profiles were determined from polished cross sections of these couples by using electron probe microanalysis with pure element standards. Interdiffusion fluxes of individual components were calculated directly from the experimental concentration profiles, and the moments of interdiffusion fluxes were examined to determine the average ternary interdiffusion coefficients. The effects of ternary alloying additions on the diffusional behavior of Ni-Cr-X alloys are presented in the light of the diffusional interactions and the formation of a protective Cr2O3 scale.

Formation and mechanical properties of Zr-Cu-Al bulk glassy alloys

Abstract We used highly purified elements (i.e. low-oxygen-content Zr metal) and a special arc melting and casting furnace to prepare Zr 50 Cu 40 Al 10 rod-shaped bulk glassy alloy over 10 mm in diameter. In the Zr-Cu-Al alloy system, we examined the glass-forming ability in the bulk glassy state by Δ T x , T g / T l , and the Hruby factor. The Hruby factor is appropriate for evaluating glass-forming ability in the cast Zr-Cu-Al bulk glassy alloy. In order to enhance the mechanical properties even in pre-oxidized Zr-Cu-Al (oxygen concentration 1000 ppm) bulk glassy alloy, we examined the effectiveness of a small addition of a fourth element. As a result, we found that the effect of adding the fourth element depends on the periodicity in the periodic table, i.e. the chemical interaction with Zr, Cu and Al elements.

Effect of W Addition on Compressive Strength of Nb–10Mo–10Ti–18Si-Base <I>In-Situ</I> Composites

Niobium solid solution/niobium silicides in-situ composites are expected to have applications in the future as high-temperature structural materials. To improve the high temperature strength further, we tried to add tungsten to Nb–10Mo–10Ti–18Si eutectic alloy by replacing Nb with 0, 5, 10 and 15 mol%W. The samples were prepared by arc casting and some of them were directionally solidified by the floating zone melting technique at a growth rate of 15 mm/h. After annealing at 1870 K for 100 h, the microstructure, Vickers hardness and high-temperature compressive strength were examined. The samples without W consisted of eutectic Nb solid solution and (Nb, Mo, Ti)5Si3 silicide, while primary Nb solid solution appeared as a result of substituting W for Nb. The microstructure of directionally solidified samples was coarse and oriented in the direction of growth, but they did not show the typical microstructure often observed in the case of directionally solidified materials. The Vickers hardness increased with increasing W content. The 0.2% yield strength (σ0.2) and the specific 0.2% yield strength (σ0.2S) (σ0.2 divided by the density) at 1670 K increased markedly with increasing W content. The directionally solidified samples showed higher σ0.2 and σ0.2S than the arc-cast samples. Even at 1770 K, the directionally solidified sample with 15 mol% W showed σ0.2 of about 650 MPa.

Sulfur segregation to growing Al2O3/alloy interfaces

It is well known that impurities and/or solutes in an alloy can segregate to the free surface and to the alloy grain boundaries at elevated temperatures [1, 2]. When a metal or alloy undergoes oxidation, an external oxide scale is formed from the transport of metal outward and of oxygen inward. It has been proposed that sulfur, which is a common impurity, segregates to the growing scale/alloy interface and weakens the interfacial bonds [3] as it does when present at alloy grain boundaries [4, 5]. However, it is not well established if sulfur should segregate to an intact interface [6], where the oxide remains adherent to the underlying alloy. Rather, the presence of sulfur that have been observed [7] is often attributed to segregation after scale detachment due to the thermal stresses present in cooling, or from accumulation as a result of oxide growth, where the interface advances inward [8]. The purpose of this paper is to report the build-up of sulfur and other impurities at growing scale/alloy interfaces to better understand the segregation phenomena associated with oxidation. Two Al2O3-forming alloys were used and their composition and sulfur content are listed in Table I. The Fe3Al-based iron aluminide was prepared by arc melting and casting, followed by hot rolling. The FeCrAl was induction melted and cast, then homogenized at 1200◦C for 24 h. The amount of sulfur in each alloy was determined using glow discharge mass spectrometry (GDMS). Specimens, typically 10 mm× 10 mm× 1 mm, were cut from the alloys with one of the main faces polished to a 1 μm finish using diamond paste. Oxidation was performed in flowing, dry oxygen at 1000◦C under 1 atm. Most specimens were air cooled after the desired oxidation time; a few were water quenched. The chemistry of the scale/alloy interface after oxidation was determined using Scanning Auger Microscopy (SAM) after the surface oxide was scratched to spallation in the ultra high vacuum (2–3× 10−10 torr) using a Vickers micro-indenter [9]; an example is given in Fig. 1. A 0.5–1 μm diameter electron beam was then placed on the exposed metal surface to study its composition. Ten to fifteen areas were surveyed to assess the compositional uniformity. The underside of the spalled oxide was also analyzed when it was exposed. Very different segregation behavior was found on the two alloys, even though both form Al2O3 scales. sulfur was the major impurity, but with significantly different concentrations. Fig. 2 shows the Auger spectra of the two interfaces at steady state. Apart from sulfur, the FeCrAl interface was also enriched with Cr and C. The concentration of interfacial sulfur with oxidation time for both alloys is plotted in Fig. 3. For the FeCrAl alloy, saturation was reached after less than 10 min. The rate is comparable in relation to sulfur diffusion in Fe [10]. For the Fe3Al alloy, on the other hand, the sulfur concentration was initially high, went through a minimum of almost no sulfur at the interface, then increased again slowly to a steady state. The same kind of trend was observed with oxidation at 900◦C, except that the rate is almost an order of magnitude slower. Furthermore, the spatial variation, as seen by the error bars, decreased considerably with time, indicating large local differences under thinner scales. Whenever the underside of the spalled scale was examined, it was found to contain only Al and O. To the free surface of the Fe3Al alloy, sulfur was found to readily segregate and reach a saturation level after about 4 min at 1000◦C [9]. Compared to this behavior, the segregation to growing Al2O3/alloy interfaces differs in a few major ways. For the FeCrAl alloy, the saturation concentration is significantly higher than the usual 0.25–0.5 monolayer coverage when S segregates to free surfaces of Fe or Ni single crystals [1]. This high concentration may be related to a cosegregation effect of S with Cr [11]. There may be some sulfide formation at the interface, whether as very small particles or as a two-dimensional compound. When

Some characteristics of YBa2Cu3Oy superconducting material obtained by arc-casting and laser melting

A superconducting Y-Ba-Cu-O with high Tc was prepared by arc casting to examine its effect on the crystalline phases in the annealed samples. X-ray diffraction (XRD) studies were carried out to investigate the orthorhombic superconducting phases. An a.c. susceptibility study was carried out and image analysis was conducted to obtain the density and grain size of the products. In addition, Nd:YAG laser melting of samples was carried out. It was found that the main crystalline phase was orthorhombic YBa2Cu3Oy and superconducting 1:2:3 crystalline phases were easily obtained by annealing in oxygen ambient and through laser melting.

Structure and Properties of Metal Hydrides Prepared by Mechanical Alloying

Our research examines the structure and reversible hydrogen storage capacity of alloys based on the LaNi{sub 5} intermetallic. The alloys are prepared by mechanical alloying (MA), a technique particularly useful when alloying LaNi{sub 5} with low melting point elements such as tin and calcium. In LaNi{sub 5-y}Sn{sub y}, x-ray diffraction and Rietveld analysis show that tin preferentially occupies the Ni(3g) sites in the LaNi{sub 5} structure, and the unit cell volume increases linearly with tin content to a maximum tin solubility of 7.33 atomic percent (LaNi{sub 4.56}Sn{sub 0.44}). The addition of tin to LaNi{sub 5} causes (a) a logarithmic decrease in the plateau pressures for hydrogen absorption and desorption, which is consistent with the corresponding increase in the volume of the LaNi{sub 5} unit cell; (b) a decrease in the hysteresis between the pressures for hydride formation and decomposition, which is in agreement with a recent theoretical model for the effect; and (c) a linear decrease in the hydrogen storage capacity. Effect (c) is explained by a rigid-band model whereby electrons donated by the tin atoms occupy holes in the 3d band of LaNi{sub 5}, which could otherwise be occupied by electrons donated by the hydrogen atoms. Thermodynamic van`t Hoffmore » analysis for these alloys show an increase in hydride formation enthalpy and no change in entropy with increasing tin concentration. LaNi{sub 5} with calcium additions shows enhanced kinetics of hydrogen absorption/desorption. The powder particles prepared by MA have a larger surface area than particles of the same overall size prepared by arc casting. All LaNi{sub 5}-based alloys prepared by MA in an inert environment require no activation for hydrogen absorption and suffer less comminution upon hydriding/dehydriding.« less

Mold filling of Ti castings using investments with different gas permeability

Objectives. The aim of this work was to study mold filling during casting of standardized five-unit Ti bridges vs. the gas permeability of the investments. Methods. An Ar arc casting machine with a separate melting and mold chamber was used. Both chambers were evacuated before Ar was introduced into the melting chamber. A rubber sealer was inserted between the top of the steel ring of the mold and the steel floor between the two chambers. The mold cavity required the same Ar pressure as the melting chamber prior to casting. Four different investments for Ti casting were investigated: 1) Bellavest T (BEGO), 2) Rematitan Plus (Dentaurum), 3) Titavest CB (Morita) and 4) Titanium Vest (Ohara Co.). Three castings were made with each investment. The molds were fired according to the manufacturers' instructions and cooled to room temperature. The Ar gas pressures in the two chambers were recorded during casting, and the mold filling was evaluated initially by visual inspection and subsequently by studying the margins of the crowns in a microscope. Results. In the melting and molding chambers, the Ar pressure was found to be: 1) Bellavest T: 400 and 1 torr; 2) Rematitan Plus: 600 and 85 torr; 3) Titavest CB: 600 and 150 torr; and 4) Titanium Vest: 600 and 85 torr, respectively. This indicates substantial differences in the gas permeability of the molds. Bellavest T produced poorly filled molds, Rematitan Plus and Titanium Vest resulted in poor margins and Titavest CB produced complete castings. Significance. Proper mold filling is promoted by investments with a high gas permeability, so the gases in the mold cavity can escape through the investment to the mold chamber.

Sn-Substituted LaNi5 Alloys For Metal Hydride Electrodes

ABSTRACTOur research examines the efficacy of tin additions to LaNi5 in improving the hydrogen storage capacity of the material during charging/discharging. Alloys were prepared using high energy ball milling (mechanical alloying), a technique superior to arc casting for alloying elements with a wide disparity in melting points. Characterization by x-ray diffraction and Rietveld analysis shows that tin preferentially occupies the Ni(3g) sites in the LaNi5 structure, and the unit cell volume increases linearly with tin content to the maximum tin solubility of 7.33 atomic percent (LaNi4.56Sn0.44). We found that powders prepared by mechanical alloying and not exposed to air require no activation to induce hydrogen absorption. The hydrogen storage capacity in the gas and electrochemical phase was measured as a function of tin content. We found that with increasing tin, the plateau pressure decreases logarithmically, whereas the hydrogen storage capacity decreases linearly.

Deformation-processed wire prepared from gas-atomized Cu-Nb alloy powders

Wires have been fabricated by deformation processing of precursor billets that were prepared from alloy powders made by high-pressure gas atomization (HPGA) of a copper-20 vol pct niobium melt. The powders were classified, and a larger size fraction, whose microstructure consisted mainly of 0.4-µm-diameter Nb dendrites, was fabricated into the precursor billet by powder metallurgical techniques. The deformation-processed wire prepared from the powder alloy billet gave significantly increased strengths at a given level of deformation strain over similar material produced by consumable arc casting. This may be attributed to the smaller initial Nb dendrite size of the alloy powder used for the precursor billet. However, the electrical conductivity of the powder material at a given strength level was significantly lower than the arccast material. The cause of the reduction of the conductivity is uncertain, and possible reasons are discussed.