Effect of compacting pressure on shape retention during supersolidus liquid phase sintering of Cu base alloys

ABSTRACT

The compacting pressure is one of the key parameters which affects sintering phenomena, such as fragmentation, rearrangement and densification. However, the type of alloy also has a similar significance which should be considered. To demonstrate the effect of the mentioned parameters, two types of copper base alloys, i.e. Cu–9Sn–8Pb and Cu–28Zn, were investigated in the present study. Prealloyed powders were compacted at 100 and 400 MPa, respectively, and sintered in the range of 890–970°C for 20 min. In situ images of the samples were taken at various sintering conditions, and the shapes were recorded. For both materials, in case of compaction at lower pressure, the gravity-induced distortion known as ‘elephant foot’ phenomenon was not observed, and the specimens show shape retention during sintering even at higher temperatures, while samples compacted at 400 MPa showed different responses to the sintering conditions: A-shaped distortion (elephant foot) occurred in the bronze alloy, while in the brass alloy O-shaped distortion was observed.

KEYWORDS:

• Cu base alloys
• supersolidus liquid phase sintering
• gravitational effect
• microstructural gradient
• compacting pressure
• elephant foot

Disclosure statement

No potential conflict of interest was reported by the author.

Notes on contributors

Mehrdad Mousapour is currently a MSc graduate in powder metallurgy. He earned his undergraduate degree in materials science and metallurgical engineering from Bu-Ali Sina University, Hamadan, Iran in October 2011. He moved to Sahand University of Technology, Tabriz, Iran and graduated with his MSc degree under the advisement of Dr. Maziyar Azadbeh (January 2015). His master’s thesis focused on comparing super solidus liquid phase sintering of copper base alloys (bronze and brass) and effect of volatile component on sintering behaviour and apparent shape of compacts during SLPS.

Maziyar Azadbeh is an Associate Professor in materials science at Sahand University of Technology, Tabriz, Iran. He has a wide background in liquid phase sintering of Cu-base alloys, surface engineering and also aluminum recycling. He started his undergraduate program in materials science at Sahand University of Technology, and obtained his MSc degree at Sharif University of Technology, Tehran, Iran in surface engineering. He continued his graduate studies at Vienna University of Technology, Vienna, Austria and graduating with his PhD under advisement of Prof. Herbert Danninger in 2006.

Herbert Danninger studied Technical Chemistry at TU Wien, obtaining his PhD in 1980. Since that time he has been doing research in powder metallurgy. In 2003 he was appointed Full Professor for Chemical Technology of Inorganic Materials at TU Wien, and currently he is also Dean of the Faculty of Technical Chemistry. He has published more than 450 articles, mostly on powder metallurgy topics, and holds 3 honorary doctorate.

ORCID

Herbert Danninger http://orcid.org/0000-0002-7205-9058