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Title:DSC/TG of Al-based alloyed powders for p/m applications
Authors:Šuštaršič, Borivoj (Author)
Medved, Jože (Author)
Glodež, Srečko (Author)
Šori, Marko (Author)
Korošec, Albert (Author)
Inštitut za kovinske materiale in tehnologije (Authorship owner)
Files:.pdf Materiali_in_Tehnologije_2014_Sustarsic_et_al._DSCTG_OF_Al-BASED_ALLOYED_POWDERS_FOR_PM_APPLICATIONS.pdf (319,52 KB)
MD5: 66FE70852AB300A099894C5B32E83963
 
URL http://mit.imt.si/Revija/izvodi/mit144/sustarsic.pdf
 
Language:English
Work type:Scientific work (r2)
Typology:1.01 - Original Scientific Article
Organization:FNM - Faculty of Natural Sciences and Mathematics
Abstract:Al-based alloyed powders, appropriate for the sintering procedure (powder metallurgy, P/M) contain the alloying elements with a high solid solubility in Al, enabling reaction and liquid-phase sintering. They are surface oxidised because of a high affinity of Al to oxygen. Besides, this type of powders contains a polymeric lubricant (wax), which reduces the friction on die walls during automatic die compaction into the final compact shape of a product. This lubricant has to be removed slowly during the first stage of sintering in order to prevent deformations and cracking of the product. Consequently, its sintering is very complex. Generally, these powders are sintered in pure nitrogen with a low dew point. The optimum sintering conditions are generally determined on the basis of light and scanning electron microscopy. The investigation can also be completed very successively with differential scanning calorimetry and thermo gravimetry. The first one allows an insight into the endo- and exothermic reactions, taking place during the heating and cooling of a compacted metal powder, and the second one allows an insight into the processes, connected with the mass loss (a reduction, a lubricant removal, etc.) or mass increase (an oxidation). The DSC/TG of three commercial Al-based alloyed powders was performed in the frame of our investigations. The results were compared with the theoretical thermodynamic-based calculations and the optimum sintering conditions were proposed.
Keywords:aluminium powders, sintering, differential scanning calorimetry and thermo gravimetry
Year of publishing:2014
Number of pages:str. 531-536
Numbering:št. 4, Letn. 48
ISSN:1580-2949
UDC:621.762.5:669.71
ISSN on article:1580-2949
COBISS_ID:18068246 New window
NUK URN:URN:SI:UM:DK:LVTZOKOK
Views:631
Downloads:68
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Record is a part of a journal

Title:Materiali in tehnologije
Shortened title:Mater. tehnol.
Publisher:Inštitut za kovinske materiale in tehnologije
ISSN:1580-2949
COBISS.SI-ID:106193664 New window

Document is financed by a project

Funder:ARRS - Agencija za raziskovalno dejavnost Republike Slovenije (ARRS)
Project no.:L2-4283
Name:Razvoj modela sistema za inteligentno podporo izbire ustreznega praškastega materiala v procesu razvoja sintranih izdelkov

Secondary language

Language:Slovenian
Title:DSC/TG prahov na osnovi Al primernih za P/M uporabo
Abstract:Legirani prahovi na osnovi Al, primerni za sinter postopek (P/M, metalurgija prahov), vsebujejo zlitinske elemente z veliko topnostjo v trdnem Al, kar omogoča reakcijsko sintranje v prisotnosti tekoče faze. Zaradi velike afinitete aluminija do kisika so na površini oksidirani. Poleg tega vsebujejo ti prahovi polimerno mazivo, ki zmanjšuje trenje na stenah orodja med avtomatskim stiskanjem prahu v končno oblikovan izdelek. To mazivo moramo v prvi fazi procesa sintranja počasi odstraniti, sicer bi lahko prišlo do nepopravljive deformacije ali celo pokanja izdelka. Zato je njihovo sintranje zelo zahtevno. Navadno se sintrajo v čisti dušikovi atmosferi z nizko temperaturo rosišča. Poleg fizikalno-kemijske karakterizacije sintranih izdelkov s svetlobno in elektronsko mikroskopijo je za določitev optimalnih pogojev sintranja zelo uporabna diferencialna vrstična kalorimetrija, kombinirana s termogravimetrijo (DSC/TG). Prva omogoča vpogled v endo- in eksotermne reakcije, ki potekajo med segrevanjem in ohlajanjem kompaktiranega kovinskega prahu, druga pa s temi procesi povezano izgubo (redukcija, odstranitev maziva itd.) ali prirastek (oksidacija) mase. V okviru naših raziskav smo izvedli DSC/TG treh komercialno dosegljivih prahov na osnovi Al, ugotovljene reakcije smo primerjali z napovedmi teoretične termodinamike in predlagali optimalne pogoje sintranja teh prahov.
Keywords:aluminijevi prahovi, sintranje, diferencialna vrstična kalorimetrija s termogravimetrijo


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