A Comparative Study on the Sintering and Casting of a Blended Elemental Ti-6Al-4V Alloy

2015 ◽  
Vol 828-829 ◽  
pp. 421-426
Author(s):  
Muziwenhlanhla A. Masikane ◽  
Hilda K. Chikwanda ◽  
Iakovos Sigalas

Over the past years, the blended elemental powder metallurgy (PM) approach has been identified as one of the most promising strategies to reduce the cost of titanium-based components. However, oxygen pick-up, inhomogeneity of the microstructure and chemical composition are sometimes reported for PM parts. This work compares properties of a blended elemental Ti-6Al-4V alloy obtained by sintering under argon gas atmosphere with those of a vacuum cast alloy. Argon was purified by passing it through a series of oxygen and moisture traps prior to being introduced into the sintering furnace. Casting was performed under vacuum (1 x 10-3 mbar). The starting material in both processes was the cold isostaticaly pressed blended elemental (BE) Ti-6Al-4V powder compact. The BE powder was prepared by mixing 60Al-40V master alloy powder with commercial Grade 4 titanium powder (0.377 wt.% O2). The sintered and cast alloys were compared on the basis of oxygen pick-up, density, microstructure, chemical composition and hardness to determine which method is better. Although the BE approach could not eliminate the common challenges associated with powder metallurgy processing of Ti alloys, oxygen pick-up and additional contamination was lower compared vacuum casting. Sintering at 1350°C for 1 h could not achieve full density compared to casting, but the microstructure appeared more homogeneous. Both sintered and cast Ti6Al4V alloys were harder than wrought Ti6Al4V due to a high concentration of interstitial oxygen. The sinterered and sintered plus HIPed Ti6Al4V alloys were softer than as-cast Ti6Al4V due to lower oxygen pick-up and incomplete densification. From the contamination and homogeneity perspective, the BE approach is an attractive technique for processing of Ti6Al4V alloy.

2017 ◽  
Vol 23 (2) ◽  
pp. 141 ◽  
Author(s):  
Pavel Salvetr ◽  
Andrea Školáková ◽  
Jaromír Kopeček ◽  
Pavel Novák

<p class="AMSmaintext">This paper deals with Ni-Ti46 and Ni-Ti-X wt. % alloys prepared by arc re-melting under argon protective atmosphere. The melting was repeated three times to obtain a homogenous chemical composition of samples. Niobium, vanadium and silicon were chosen as alloying elements and they were added into the alloy in an amount of 5 wt. %. Microstructure, phase composition, hardness and transformation behaviour were investigated parameters. Properties of cast alloys are compared with alloys of the same chemical composition prepared by powder metallurgy method – self-propagating high-temperature synthesis (SHS). Arc re-melting produced a more homogeneous microstructure with a lower content of the Ti<sub>2</sub>Ni phase than powder metallurgy methods in case of Ni-Ti-X alloys. Quite a high amount of the secondary phase (a mixture of the Ni<sub>2</sub>Ti, NiTi and Ti<sub>2</sub>Ni phases) was created in the microstructure of Ni-Ti46 wt. % alloy. The addition of silicon caused an increase of transformation temperatures and hardness.</p>


2018 ◽  
Vol 941 ◽  
pp. 1276-1281
Author(s):  
Anna Terynková ◽  
Jiří Kozlík ◽  
Kristína Bartha ◽  
Tomáš Chráska ◽  
Josef Stráský

Ti-15Mo alloy belongs to metastable β-Ti alloys that are currently used in aircraft manufacturing and Ti15Mo alloy is a perspective candidate for the use in medicine thanks to its biotolerant composition. In this study, Ti15Mo alloy was prepared by advanced techniques of powder metallurgy. The powder of gas atomized Ti-15Mo alloy was subjected to cryogenic milling to achieve ultra-fine grained microstructure within the powder particles. Powder was subsequently compacted using spark plasma sintering (SPS). The effect of cryogenic milling on the microstructure and phase composition of final bulk material after SPS was studied by scanning electron microscopy. Sintering at 750°C was not sufficient for achieving full density in gas atomized powder, while milled material could be successfully sintered at this temperature. Alpha phase particles precipitated during sintering and their size, as well as the size of beta matrix grains, was strongly affected by the sintering temperature.


2016 ◽  
Vol 704 ◽  
pp. 75-84 ◽  
Author(s):  
Fei Yang ◽  
Brian Gabbitas ◽  
Ajit Pal Singh ◽  
Stella Raynova ◽  
Hui Yang Lu ◽  
...  

Blended Elemental Powder Metallurgy (BE-PM) is a very attractive method for producing titanium alloys, which can be near-net shape formed with compositional freedom. However, a minimization of oxygen pick-up during processing into manufactured parts is a big challenge for powder metallurgy of titanium alloys. In this paper, different approaches for preparing titanium alloy parts by powder compact extrusion with 0.05-0.1wt.% of oxygen pick-up during manufacturing are discussed. The starting materials were a powder mixture of HDH titanium powder, other elemental powders and a master alloy powder. Different titanium alloys and composites, such as Ti-6Al-4V, Ti-4Al-4Sn-4Mo-0.5Si, Ti-5Al-5V-5Mo-3Cr, and Ti-5Al-5V-5Mo-3Cr-5vol%TiB, with different profiles such as round and rectangular bars, a wedge profile, wire and tubes have been successfully manufactured on a laboratory and pilot-plant scale. Furthermore, a possible route for scaling up the titanium processing capabilities in the University of Waikato has also been discussed.


2012 ◽  
Vol 560-561 ◽  
pp. 1011-1015
Author(s):  
Yang Huan Zhang ◽  
Tai Yang ◽  
Hong Wei Shang ◽  
Ying Cai ◽  
Hui Ping Ren ◽  
...  

The RE–Mg–Ni-based A2B7-type La0.75−xPrxMg0.25Ni3.2 Co0.2Al0.1 (x = 0, 0.1, 0.2, 0.3, 0.4) electrode alloys were fabricated by casting and melt spinning. The microstructures and electrochemical characteristics of the as-cast and spun alloys were investigated in detail. The results indicate that the as-cast and spun alloys have a multiphase structure, consisting of two main phases (La, Mg)2Ni7 and LaNi5 as well as a residual phase LaNi2. The substitution of Pr for La results in a notable grain refinement of the as-cast alloys without altering the phase structure of the alloys. The discharge capacity of the alloys first rises and then falls with the variation of the Pr content. As Pr content grows from 0 to 0.4, the discharge capacity increases from 389.4 (x = 0) to 392.4 (x = 0.1) and then drops to 383.7 mAh/g (x = 0.4) for the as-cast alloy. And it mounts up from 393.5 (x = 0) to 397.9 (x = 0.1) and then declines to 382.5 mAh/g for the as spun (5 m/s) alloys. Furthermore, the measurements of the electrochemical hydrogen storage kinetics reveal that the high rate discharge ability (HRD), the limiting current density (IL) and the hydrogen diffusion coefficient (D) of the alloys first increases then decreases with the rising amount of Pr substitution.


2004 ◽  
Vol 19 (5) ◽  
pp. 1531-1538 ◽  
Author(s):  
Guangyin Yuan ◽  
Kenji Amiya ◽  
Hidemi Kato ◽  
Akihisa Inoue

The structure and mechanical properties of Mg–Zn–Al–Y base cast alloys containing an icosahedral quasicrystal phase (i-phase) as a main strengthening phase were investigated. Mg–8Zn–4Al–xY base bulk alloys containing the i-phase were prepared by casting into a copper mold at moderate cooling rates. The Y addition was effective for decreasing the size of the i-phase and the increasing the homogeneity of its dispersed state. The mechanical properties examined by compression tests at room temperature were much superior to those of a conventional AZ91 Mg alloy. The creep tests at elevated temperatures indicated a promising high temperature creep resistance of the quasicrystal-reinforced Mg–Zn–Al–Y cast alloy. The strengthening mechanism was also discussed.


2020 ◽  
Vol 4 (2) ◽  
pp. 577-583
Author(s):  
M. B. Usman ◽  
O. S. Aaasa ◽  
O. S. Balogun ◽  
U. F. Yahaya

This study investigated the marketing of frozen fish in Kaduna metropolis, Kaduna state. Ten (10) markets were purposively selected due to high concentration of frozen fish marketers and the volume of trading activities; Primary data were generated through the use of structured questionnaire administered to hundred (100) randomly selected retailers and fifteen (15) purposively selected wholesalers. The data were analyzed using descriptive statistic, budgeting technique, net marketing and rate of return on capital invested. The result show that majority 80 percent and 53 of the retailers and wholesalers were female, Majority (70prcent) of the retailers had primary education but most of the wholesaler’s attained tertiary education. The frozen fish marketing channels identified in the area are made up of zero and multi stage channels. Furthermore, the cost and return analysis revealed that the wholesalers realized about N121, 000.00 naira while the retailers got N56, 000.00 naira per month while return to per capital invested (RPCI) was 11 kobo and 22 kobo per Naira invested for the wholesalers and the retailers respectively. This implies that the enterprise is profitable. Transportation difficulties and marketing charges ranked were major constraints confronting frozen fish marketers. It is recommended that provision of good roads network and formidable integrated marketing system will further improve the profitability of the enterprise in the study area.


2019 ◽  
Vol 70 (7) ◽  
pp. 2315-2320
Author(s):  
Victor Geanta ◽  
Robert Ciocoiu ◽  
Ionelia Voiculescu

The scientific paper presents a numerical modeling of the chemical composition for the optimization of the multicomponent light alloys in the Al-Mg-Ca-Si-B system. The effects of the proportion of each chemical element on the main characteristics of the alloy based on the mixture rule and the correlation between the melting temperature and the modulus of elasticity were analyzed numerically. The model results has reveals that even other factors must be taken into account, i.e. the mechanical characteristics which varied significantly with changing of chemical compositions. A compromise was set, by slightly increasing the density to acquire better mechanical characteristics. The selected chemical composition was then used to obtain the new low density alloy. In current research stage we conclude that the as cast alloy comprises an inhomogeneous solid solution and complex oxides. Further studies are ongoing on the experimental alloy in various states (homogenization annealed and processed by plastic deformation).


Author(s):  
Hamza Mohamed Ahmed ◽  
Ashraf Mahmoud Ramadhani ◽  
Ibrahim Yaagoub Erwa ◽  
Omer Adam Omer Ishag ◽  
Mohamed Bosharh Saeed

cinnamon dating from 1000 AD when it was firstly recorded in English due to its important as aroma and as herbs. The aim of this study was to investigate phytochemicals constitutes, chemical composition and antimicrobial activity of the essential oil of commercial samples of Cinnamon verum bark. The essential oil was extracted by hydrodistillation, while the crude extracts were prepared by three different solvents methanol (70%), acetone and aqueous. Phytochemical screening of crude extracts was performed using standard methods. The essential oil was subjected to GC-MS analysis and tested against Staphylococcus aureus, Salmonella typhimurium, Pseudomonas aeruginosa, Eschericchia coli and Candida albicans. The obtained results indicated the presence of alkaloids, flavonoids, coumarin, tannins, terpenoids, saponin, glycoside, anthrocyanin and phenolic compounds in the methanolic, aqoueous and acetone extracts of C. verum bark; while the major components of the extracted essential oil of C. verum bark were cinnamaldehyde (85.50%), stigmasterol (3.69%), Cadinene (1.37%), (E)-cinnamaldehyde (1.35%), alpha-amorphene (1.33%), hydrocinnamaldehyde (1.28%), alpha-cubebene (1.25) and ergosterol (1.09%) respectively. The antimicrobial activity result indicated the high activity of the extracted essential oil against all tested microorganisms at high concentration; except in S. typhimurium and C. albicans at concentrations of 25% and 12.5% no activity was noticed. Based in our obtained results the essential oil of C. verum bark had high potential as antimicrobial agent, therefore, recommended for more advanced studies to be conducted on this abundant plant as natural source of antibiotics.


2021 ◽  
Vol 48 (2) ◽  
pp. 148-161
Author(s):  
R. S. Onabanjo ◽  
G. S. Ojewola ◽  
D. N. Onunkwo ◽  
O. O. Adedokun ◽  
E. U. Ewa ◽  
...  

The growing concern about the cost of feed ingredients, use of least cost feed formulation and maintenance of a reliable nutritional requirement for broiler birds irrespective of the season is almost compelling to look for alternatives. Thus, this experiment was conducted to evaluate the performance of broiler chickens fed rice milling waste (RMW) as a replacement for maize. Chemical composition of rice milling waste was determined, while eleven experimental diets each were formulated to contain RMW as replacement for maize at 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% and 100%. Three hundred (300), 7-day-old chicks were allocated to the 11 dietary treatments each having 3 replicate pens with 10 birds per pen in a Completely Randomized Design (CRD). Feed and water were provided ad libitum for 6 weeks. Growth performance, carcass yield, organ proportions and economics of production were monitored. Data were subjected to ANOVA at P<0.05. The result from the chemical composition showed that rice milling waste has 89.84% dry matter, 10.80% crude protein and 24.09% crude fibre, while the gross energy was 3789 kcal/g, this showed that RMW is suitable as feed ingredient and as well would not hinder absorption and nutrient utilization. The result of the growth performance showed that broiler chickens fed 10% - 40% RMW had greater average daily weight gain (55.33g- 47.97g), reached a greater slaughter and carcass weight (1500g – 1650g) and were more feed efficient than broiler chicken of the other treatments (P<0.05 for each). In addition, from an economical point of view birds fed 10 - 40% were superior to the other treatments where the cost/kg weight gained (N292.21K – N315.96K) were lower than the remaining treatment groups. Thus, the inclusion of RMW in diet of broiler chickens as a replacement for maize improved nutrient utilization and economic value. It can therefore be recommended that RMW can be used to replace maize between 10% -40% in the diets of broiler chickens.     La préoccupation croissante au sujet du coût des ingrédients alimentaires, de l'utilisation de la formulation d'aliments pour animaux les moins coûteux et du maintien d'une exigence nutritionnelle fiable pour les oiseaux de gril, quelle que soit la saison, est presque convaincante pour chercher d'autres solutions. Ainsi, cette expérience a été menée pour évaluer la performance des poulets à griller nourris aux déchets de fraisage du riz (le 'RMW') comme remplacement du maïs. La composition chimique des déchets de fraisage du riz a été déterminée, tandis que onze régimes expérimentaux ont été formulés pour contenir le 'RMW' comme remplacement pour le maïs à 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% et 100%. Trois cents (300), poussins de 7 jours ont été alloués aux 11 traitements diététiques ayant chacun 3 stylos de répétition avec 10 oiseaux par stylo dans un design complètement randomisé (CRD). L'alimentation et l'eau ont été fournies ad libitum pendant 6 semaines. Les performances de croissance, le rendement de la carcasse, les proportions d'organes et l'économie de la production ont été surveillés. Les données ont été soumises à ANOVA (P<0.05) Le résultat de la composition chimique a montré que les déchets de fraisage du riz ont 89,84% de matière sèche, 10,80% de protéines brutes et 24,09% de fibres brutes, tandis que l'énergie brute était de 3789 kcal/g, ce qui a montré que le 'RMW' est approprié comme ingrédient d'alimentation et ainsi n'entraverait pas l'absorption et l'utilisation des nutriments. Le résultat de la performance de croissance a montré que les poulets a griller nourris 10% - 40% RMW avaient un gain de poids quotidien moyen plus élevé (55.33g- 47.97g), ont atteint un plus grand poids d'abattage et de carcasse (1500g - 1650g) et étaient plus économes en aliments pour des animaux que le poulet de gril des autres traitements (P<0.05 pour chacun). En outre, d'un point de vue économique, les oiseaux nourris de 10 à 40 % étaient supérieurs aux autres traitements où le coût/kg de poids gagné (N292.21 K – N315.96 K) était inférieur à celui des autres groupes de traitement. Ainsi, l'inclusion du RMW dans l'alimentation des poulets de poulet a griller comme remplacement du maïs a amélioré l'utilisation des nutriments et la valeur économique. Il peut donc être recommandé que le 'RMW' peut être utilisé pour remplacer le maïs entre 10% -40% dans les régimes des poulets à griller.


2018 ◽  
Vol 212 ◽  
pp. 01023 ◽  
Author(s):  
Vasily Vorobchuk ◽  
Maria Matveeva ◽  
Artem Peshkov

Decorative concrete refers to a special kind of concrete. Products made of decorative concrete must meet, in addition to the increased requirements for appearance, certain architectural expressiveness and also certain indicators for strength, durability, and environmental friendliness. In addition, one should strive to reduce the cost of both decorative concrete and products made of such concrete. The analysis is carried out, experimental researches of qualitative indicators of industrial man-caused wastes are also studied: carbide lime, fluoride, sludge-lignin, their material and chemical composition. The possibility of using the analyzed industrial wastes as raw materials for production of white and color cements is established. The physicomechanical properties of the obtained cements and decorative concretes on their basis are studied, the economic efficiency of the proposed technology is determined.


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