Novel uses of electric fields and electric currents in powder metal (P/M) processing

Newman, D.C.

doi:10.1016/s0921-5093(00)00776-0

Cited by 10 publications

(5 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…SPS is also known as FAST, electric discharge compaction/consolidation (EDC), pulsed electric current sintering (PECS), plasma pressure compaction (P 2 C), pulse electric discharge process (PEDP), plasma activated sintering (PAS), electric field sintering, plasma pressure consolidation, pulse current pressure sintering (PCPS) and pulsed current hot pressing (PCHP). SPS is a non-conventional and versatile sintering technique for the rapid consolidation of metal or ceramic powders within a much shorter processing time and at lower temperatures compared to conventional PM processes [23,24,25,26]. The power consumption during SPS consolidation is about one-third to one-fifth of that of traditional techniques, including pressure-less sintering, hot pressing and hot isostatic pressing.…”

Section: Introductionmentioning

confidence: 99%

“…The success of the SPS method as a novel sintering method has been attributed to the role of the plasma that is generated between particles [24]. The action of this plasma to eliminate surface impurities is reported to be the reason for the observed enhanced sintering.…”

Section: Introductionmentioning

confidence: 99%

“…During SPS, mechanical pressure is applied to compact powder in a die/punch set-up, while in situ generating very fast Joule heating by means of a high pulsed DC current flow. The success of the SPS method as a novel sintering method has been attributed to the role of the plasma that is generated between particles [ 24 ]. The action of this plasma to eliminate surface impurities is reported to be the reason for the observed enhanced sintering.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Spark Plasma Sintering As a Solid-State Recycling Technique: The Case of Aluminum Alloy Scrap Consolidation

et al. 2014

View full text Add to dashboard Cite

Recently, “meltless” recycling techniques have been presented for the light metals category, targeting both energy and material savings by bypassing the final recycling step of remelting. In this context, the use of spark plasma sintering (SPS) is proposed in this paper as a novel solid-state recycling technique. The objective is two-fold: (I) to prove the technical feasibility of this approach; and (II) to characterize the recycled samples. Aluminum (Al) alloy scrap was selected to demonstrate the SPS effectiveness in producing fully-dense samples. For this purpose, Al alloy scrap in the form of machining chips was cold pre-compacted and sintered bellow the solidus temperature at 490 °C, under elevated pressure of 200 MPa. The dynamic scrap compaction, combined with electric current-based joule heating, achieved partial fracture of the stable surface oxides, desorption of the entrapped gases and activated the metallic surfaces, resulting in efficient solid-state chip welding eliminating residual porosity. The microhardness, the texture, the mechanical properties, the microstructure and the density of the recycled specimens have been investigated. An X-ray computed tomography (CT) analysis confirmed the density measurements, revealing a void-less bulk material with homogeneously distributed intermetallic compounds and oxides. The oxide content of the chips incorporated within the recycled material slightly increases its elastic properties. Finally, a thermal distribution simulation of the process in different segments illustrates the improved energy efficiency of this approach.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Spark Plasma Sintering As a Solid-State Recycling Technique: The Case of Aluminum Alloy Scrap Consolidation

et al. 2014

View full text Add to dashboard Cite

show abstract

“…However, often they have ignored the local heat balances and EM field amplification factors caused by pores inside the powder compact as done for example by Olevsky and Froyen (2006). Furthermore investigators of these techniques such as Mishra and Mukherjee (2000), Newman (2000) and Kodash et al (2004) have reported plastic phenomena not so easily explainable with simple resistive heating and consequent lower strength and higher ductility of the powders under process. There are strong experimental evidences that diffusivity is enhanced and driven by the EM field as observed by Pierce and Brusius (1997) and Bertolino et al (2001) and that plasticity is enhanced by the flow of electrical currents through conductors from the electro-plastic effect, EPE, as explained by Troitskii (1975Troitskii ( , 1976Troitskii ( , 1977 and Conrad (2000Conrad ( , 2001Conrad ( , 2002Conrad ( , 2005.…”

Section: Introductionmentioning

confidence: 99%

Processing characteristics and parameters in capacitor discharge sintering

Fais

2010

Journal of Materials Processing Technology

View full text Add to dashboard Cite

“…Different researchers have performed important advances in the creation of hybrid processes with the goal of resolving the limitations of many conventional processes, especially when very hard materials must be mechanized. Some examples include the improvement of the silicon carbide (SiC) milling process when is assisted with electric charges studied by Renjie et al (2011) [38]; the improvements of surface roughness when the modification process is assisted by an electro-chemical finish as reported by Pa (2008) [39]; the electro-chemically assisted burnishing process also shows improvements in surface roughness as presented by Newman (2000) [40], and finally, a machining enhancement when AZ91 alloy was previously assisted with current pulses during a rolling process, studied by Zhang et al (2012) [41]. They concretely reported how the product machinability improved by decreasing the cutting forces and the surface roughness.…”

Section: Introductionmentioning

confidence: 99%

Electropulsing to assist conventional manufacturing processes

Sánchez Egea

View full text Add to dashboard Cite

This thesis presents a study on the variation of the mechanical properties of some materials. These variations are registered for processes as bottom bending, wire drawing or round turning, which are performed under high density electropulses. This research implied the study of several issues related to the manufacturing processes and the electric pulses. For example, some isolated systems are developed for each process. This is required for protecting the monitoring devices and machinery from electric drifts. On the other hand, several electropulse generators are designed and manufactured to electrically assist the aforementioned manufacturing processes. The electrical connectors is the main technological issue in each process to ensure good electrical contact during experimentation. Once the manufacturing setup is under control, electropulses are applied on various materials whilst its physical properties are measured and recorded. In particular, the processes are achieved under different electric configurations to infer the influence of the electropulses. The obtained results show that different mechanical and manufacturing properties like elastic restoring forces, yield strength, power consumption, surface roughness and material hardness among others are modified when the manufacturing process is assisted with a pulsed electric field. Additionally, the machinability and formability is improved when the metallic material is affected by current pulses. However, it should be noted that the mechanical properties behavior under different electrical parameters, like current density, frequency discharge and pulse duration, is complex and does not follow an expected relationship. Furthermore, numerical simulation analyses is required to study and understand the complex behavior of the mechanical properties. The manufacturing process of bending, machining and drawing process was done at the Universitat Politècnica de Catalunya (Spain) in collaboration with the Northwestern University (USA), the Universidad Pontificia Universidad Católica de Chile (Chile) and the Universidad Tecnológica de Pereira (Colombia). This thesis is funded by the Ministry of Economy and Competitiveness of Spain, reference project: DPI2011-26326 (grant no. BES-2012-056760). Along the document detailed information on methodology for the aforementioned processes and some conclusions are provided En el presente estudio se documenta la variación de las propiedades mecánicas registradas en diversos procesos de fabricación, doblado, mecanizado y trefilado, cuando estos procesos son asistidos con generadores de pulsos de alta densidad de corriente Para cada proceso de fabricación se ha realizado un utillaje específico para aislar eléctricamente la máquina de ensayo. Esto permite inducir los pulsos de corriente únicamente a través de las probetas metálicas, sin correr el riesgo de inhabilitar las máquinas de fabricación. Varios generadores de pulsos de corriente han sido diseñados y fabricados a lo largo de la tesis para asistir eléctricamente los procesos de fabricación mencionados. Para cada estudio se varía el área de contacto de los conectores eléctricos con el material para asegurar un buen contacto eléctrico durante la experimentación. La influencia de los pulsos de corriente eléctrica en los diferentes materiales manufacturados ha sido registrada y estudiada por varios equipos de medida. Además, se ha necesitado de programas de simulación numérica para estudiar y comprender el comportamiento de las propiedades mecánicas. Los resultados obtenidos en este trabajo demuestran que varias propiedades mecánicas como la recuperación elástica, esfuerzos de fluencia, potencia consumida, rugosidad superficial y dureza del material entre otras son modificadas cuando los procesos de fabricación son asistidos por un campo eléctrico. En resumen, se observa que la maquinabilidad del material metálico mejora cuando es fabricado bajo la influencia de los pulsos eléctricos. Esto es debido a que se reduce los esfuerzos de fluencia, mejora la rugosidad superficial, se atenúa la recuperación elástica y disminuye su dureza superficial. Aun así, cabe indicar que el comportamiento de las propiedades mecánicas anteriores bajo las condiciones eléctricas son complejas y no siguen una relación trivial. Indicar que los avances en el área de fabricación realizados en este trabajo en los procesos de doblado, mecanizado y trefilado han sido realizados en la Universitat Politècnica de Catalunya (UPC), Escola Universitaria d'Enginyeria Tècnica Industrial de Barcelona (EUETIB) en colaboración con la Pontificia Universidad Católica de Chile (PUC), la Universidad Tecnológica de Pereira (UTP) y la Northwes tern University. En consecuencia, a lo largo del documento se detalla la metodología de estudio y los resultados obtenidos de los diferentes procesos mencionados, comparando los procesos convencionales respecto a los asistidos. Además, se estudiará en profundidad la influencia de los pulsos de corriente en el comportamiento de las principales propiedades mecánicas, según el proceso.

show abstract

Novel uses of electric fields and electric currents in powder metal (P/M) processing

Cited by 10 publications

References 0 publications

Spark Plasma Sintering As a Solid-State Recycling Technique: The Case of Aluminum Alloy Scrap Consolidation

Spark Plasma Sintering As a Solid-State Recycling Technique: The Case of Aluminum Alloy Scrap Consolidation

Processing characteristics and parameters in capacitor discharge sintering

Electropulsing to assist conventional manufacturing processes

Contact Info

Product

Resources

About