Powder metallurgy of high density W-Ni-Cu alloys

Download

index.pdf

Date

2006

Author

Çalışkan, Necmettin Kaan

Metadata

Show full item record

Item Usage Stats

199
views

379
downloads

In the present study; the effects of the powder metallurgical parameters such as the mixing method, compaction pressure, initial tungsten (W) particle size, composition, sintering temperature and sintering time on the sintering behavior of selected high density W-Ni-Cu alloys were investigated. The alloys were produced through conventional powder metallurgy route of mixing, cold compaction and sintering. The total solute (Ni-Cu) content in the produced alloys was kept constant at 10 wt%, while the copper concentration of the solutes was varied from 2.5 wt% to 10 wt%. Mainly liquid phase sintering method was applied in the production of the alloys. The results of the study were based on the density measurements, microstructural characterizations including optical and scanning electron microscopy and mechanical characterizations including hardness measurements. The results showed that the nature of the mixing method applied in the preparation of the powder mixtures has a considerable effect on the final sintered state of W-Ni-Cu alloys. Within the experimental limits of the study, the compaction v pressure and initial W particle size did not seem to affect the densification behavior. It was found that the sintering behavior of W-Ni-Cu alloys investigated in this study was essentially dominated by the Ni content in the alloy and the sintering temperature. A high degree of densification was observed in these alloys with an increase in the Ni content and sintering temperature which was suggested to be due to an increase in the solubility and diffusivity of W in the binder matrix phase with an increase in these parameters, leading to an increase in the overall sintering kinetics. Based on the results obtained in the present study, a model explaining the kinetics of the diffusional processes governing the densification and coarsening behavior of W-Ni-Cu alloys was proposed.

Subject Keywords

Metallurgy.

URI

http://etd.lib.metu.edu.tr/upload/2/12607576/index.pdf
https://hdl.handle.net/11511/16360

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Indigo dyeing wastewater reclamation by membrane-based filtration and coagulation processes Unlu, M.; Yukseler, H.; Yetiş, Ülkü (Elsevier BV, 2009-05-15) In the present study. the possibility to reuse the indigo dyeing rinsing wastewater originating from a denim textile mill was investigated. Coagulation and filtration processes were selected as the pretreatment alternatives and applied to dyeing wastewater samples. Both physicochemical pretreatment alternatives and nanofiltration technique were optimized to produce an effluent satisfying the reuse criteria for the textile industry. The results showed that coagulation is not all effective and efficient pretr...
Preparation and characterization of supported PES membranes TOPUZ, BERNA; Yılmaz, Levent; Kalıpçılar, Halil (Journal of the Faculty of Engineering and Architecture of Gazi University, 2019-01-01) In the present study. polyethersulfone (PES) membranes on a macroporous alumina support was prepared by solvent-deposition method to separate H-2/CH4 mixture. The membrane solution viscosities were determined in order to understand the effect of PES concentration on the formation of selective membranes over a support. Supported PES membranes were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and single gas permeability measurements of H-2 and CH4. The membrane casting solution...
Alu insertion polymorphisms in Anatolian Turks Dinç, Havva; Togan, İnci Zehra; Department of Biological Sciences (2003) In the present study; ten autosomal human-specific Alu insertion polymorphisms; ACE, APO, A25, B65, D1, FXIIIB, HS4.32, HS4.69, PV92 and TPA25 were analyzed in approximately 100 unrelated individuals from Anatolia. Alu insertion polymorphisms offer several advantages over other nuclear DNA polymorphisms for human evolution studies. The frequencies of the ten biallelic Alu insertions in Anatolians were calculated and all systems were found to be in Hardy-Weinberg equilibrium (p>0.05). By combining the result...
Motorcycle accidents, rider behaviour, and psychological models Özkan, Türker; DOĞRUYOL, Burak; YILDIRIM, Zumrut; ÇOYMAK, Ahmet (2012-11-01) The aims of the present study were to: (a) investigate the factor structure of the Motorcycle Rider Behaviour Questionnaire (MRBQ) [Elliott, MA, Baughan, B.J., Sexton, B.F., 2007. Errors and violations in relation to motorcyclists' crash risk. Accident Analysis and Prevention 39, 491-499] in among Turkish riders, and (b) study the relationships between different types of rider behaviour and motorcyclists' active and passive accidents and offences, and (c) investigate the usefulness of the Theory of Planned ...
Intergroup relations in a changing political context: the case of veiled and unveiled university students in Turkey Hortacsu, N (Wiley, 2000-09-01) The present study investigated (a) the underlying dimensions of different measures related to identification , categorization, ingroup, bias and contact conditions, and (b) relations between two groups related to an important social controversy over time. Questionnaires were administered to veiled (minority) and unveiled (majority) Turkish female university students during the fall of 1996 and the spring of 1998. Results of factor analysis revealed three factors, namely: tolerance, including percieved outgr...

Citation Formats

N. K. Çalışkan, “Powder metallurgy of high density W-Ni-Cu alloys,” M.S. - Master of Science, Middle East Technical University, 2006.