Internal or Die Wall Lubrication for Compaction of Al Powders?

Kehl, W.L.; Bugajska, Monika; Fischmeister, H. F.

doi:10.1179/pom.1983.26.4.221

Cited by 17 publications

(11 citation statements)

References 1 publication

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“…Following this work, there have been a number of studies on admixed and die wall lubrication. Examples include works by Kehl et al (1983), Li et al (1996), Briscoe and Ozkan (1997), Turenne et al (1999), Li et al (2002) and Simchi (2003). Consistently, these works have highlighted the benefit to be derived from die wall lubrication, but its practical application in an industrial setting still remains a challenge.…”

Section: Lubricationmentioning

confidence: 88%

Friction measurement and lubrication in unloading and ejection stages in powder pressing cycle

Korachkin¹,

Gethin²,

Lewis³

et al. 2008

Powder Metallurgy

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The development of a floating die shear plate apparatus and its use to explore lubrication mechanisms (both admixed and die wall) and to assess the effectiveness of lubrication under a wide range of both compaction and normal loading conditions are described. The equipment allows the independent exploration of the effect of density and normal stress on the friction between compact and tool set surface. Tests were carried out using DistaloyAE, a zirconia target surface and Kenolube as lubricant (added or applied). A friction correlation that includes both density and normal stress effects and that reduces in response to both of these parameters was found. The results also suggest that the friction coefficient during ejection will be lower than that during compaction; at very high contact stresses, there is a likelihood that the lubrication regime will break down leading to galling. With regard to the friction mechanism, surface analysis using EDX did not detect the presence of lubricant on the compact surface; however, it did reveal two distinct pore types, a 'dark' one having a higher than average level of carbon and a 'light' one having a higher than average level of nickel. Image and topographical measurement of compacts subjected to sliding against the target surface revealed significant differences. Both analyses suggested significant closure of open pores due to sliding with topographical analysis revealing remnants of pores under the deformed particles that make up the exterior of the compact surface. Results confirmed there is no noticeable benefit in increasing admixed lubricant content above 0?5%. Die wall lubricant was demonstrated to be very effective, achieving a reduction in friction of up to 58% for unlubricated powder and up to 27% for powder containing 0?5% admixed lubricant. This was achieved for a lubricant film of typical thickness 5-20 mm.

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Section: Lubricationmentioning

confidence: 88%

Friction measurement and lubrication in unloading and ejection stages in powder pressing cycle

Korachkin¹,

Gethin²,

Lewis³

et al. 2008

Powder Metallurgy

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“…In general, the admixed lubrication is more productive and economical process than die-wall lubrication in powder metallurgy (P/M) process. However, in admixed lubrication, residual lubricants between powder particles interfere with inter-particle diffusion during sintering process, resulting in deterioration of mechanical properties of sintered Al P/M alloys [2][3][4][5][6][7][8][9]. In the present study, a newly developed lubricant mixture is proposed to improve sintered properties of Al-Cu-Mg P/M alloy, and its de-lubrication behavior is investigated.…”

Section: Introductionmentioning

confidence: 99%

“…Al and Al alloys are most popular and widely used in lightweight engineering structures and components. Especially, Al alloys produced by powder metallurgy (P/M) processes are successfully replacing heavy Fe-based P/M alloys for manufacturing automotive parts [1,2].…”

Section: Introductionmentioning

confidence: 99%

De-Lubrication Behavior Of Novel EBS Based Admixed Lubricant In Aluminum P/M Alloy

Seok

Kim³

et al. 2015

Archives of Metallurgy and Materials

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The objective of the present research is to develop a novel lubricant for Al-Cu-Mg P/M alloy and to address the effects of the lubricant and compaction pressure on sintered properties. A lubricant mixture consisting of Ethylene Bis Stearamide, Zn-Stearate, and fatty acid was newly developed in this study, and the de-lubrication behavior was compared with that of other commercial lubricants, such as Ethylene Bis Stearamide, Zn-Stearate, and Al-Stearate. Density and transverse rupture strength of sintered materials with each lubricant were examined, respectively. The microstructural analysis was conducted using optical microscope.

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“…The sintering response of Alumix 123 has been studied in the laboratory [5][6][7][8] where liquid phase sintering mechanisms have been elucidated and sintering procedures have been developed to illicit optimum mechanical properties on the laboratory scale. However, there is less work available in the open literature on the industrial sintering response and microstructural characterization of Alumix 123.…”

Section: Introductionmentioning

confidence: 99%

Industrial Sintering Response and Microstructural Characterization of Aluminum Powder Metallurgy Alloy Alumix 123

Judge

Bishop

Kipouros

2017

Metallogr. Microstruct. Anal.

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In this work, the industrial sintering response of the commercial aluminum powder metallurgy alloy 'Alumix 123' has been examined and the resulting microstructure investigated by optical microscopy, scanning electron microscopy, energy-dispersive x-ray spectroscopy, and x-ray diffraction. Alumix 123 is similar in composition to wrought aluminum alloy 2014 and was revealed to develop a sintered density of 92% of theoretical using standard practices for industrial sintering. Microstructural investigations proved that as a result of industrial sintering, a number of embrittling iron-containing intermetallics are developed in addition to the desirable copper-rich intermetallics. To improve the density of sintered components, procedures were developed for secondary processing by 'sizing' (repressing) in a laboratory setting. The results showed that sizing to the industry standard reduction in height of 5% only closed a portion of open surface porosity and that higher sizing pressures should be used in applications that are sensitive to this microstructural feature.

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Internal or Die Wall Lubrication for Compaction of Al Powders?

Cited by 17 publications

References 1 publication

Friction measurement and lubrication in unloading and ejection stages in powder pressing cycle

Friction measurement and lubrication in unloading and ejection stages in powder pressing cycle

De-Lubrication Behavior Of Novel EBS Based Admixed Lubricant In Aluminum P/M Alloy

Industrial Sintering Response and Microstructural Characterization of Aluminum Powder Metallurgy Alloy Alumix 123

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