The role of pore evolution during supersolidus liquid phase sintering of prealloyed brass powder

ABSTRACT

The aim of this research is to study the pore structure as well as to assess the liquid phase sintering behaviour of Cu-28Zn powder specimens at different green density levels and temperatures. For this purpose, samples were compacted to obtain six different green densities and then sintered at 870°C, 890°C and in part at 930°C for 30 min. The results revealed that the spherical pores which are formed inside the grains can be swept by grain boundaries due to grain growth and join to primary pores so that secondary intragranular pores are eliminated and intergranular pores enlarged at higher temperatures. Also, the pores move upwards to the top of sample due to buoyancy forces. The role of pore structure in distortion is more tangible at higher temperatures (930°C) so that O-shape and X-shape distortions were observed at high and low green density samples, respectively.

KEYWORDS:

• Supersolidus liquid phase sintering
• prealloyed brass powders
• green density
• pore structure and distortion

Disclosure statement

No potential conflict of interest was reported by the author(s).

Notes on contributors

Somayeh Ghasemi is currently a Ph.D. student in Materials Science and Engineering at Sahand University of Technology, Tabriz, Iran. She is working in the field of 3D printing of Porous Materials. She also received both B.Sc. and M.Sc. degrees from Sahand University of Technology in 2013 and 2016, respectively.

Maziyar Azadbeh is a Professor in materials science at Sahand University of Technology, Tabriz, Iran. He has a wide background in high strength Cr alloyed sintered steels, 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 corrosion and protection of materials. He continued his graduate studies at Vienna University of Technology, Vienna, Austria and got his PhD under supervision of Prof. Herbert Danninger in 2006.

Mehrdad Mousapour is studying his second Master Program in Metals Processing at Aalto University, Finland. He obtained his first M.Sc degree in Materials Engineering (Powder Metallurgy) at Sahand University of Technology in 2015, and his B.Sc degree in Materials Engineering (industrial metallurgy) at Bu-ali Sina University in 2011. He is currently working on 3D printing project.

Ahad Mohammadzadeh was born in Tabriz, Iran, in 1987. He received his B.Sc. in Materials Engineering, as well as his M.Sc. and Ph.D. from the Sahand University of Technology, Tabriz, Iran, in 2010, 2012, and 2016, respectively. In 2017, he joined the Department of Materials Engineering, University of Maragheh, as an assistant professor. His current research interests include powder metallurgy, metal-oxide nanomaterials, heat treatment, and surface engineering. Dr. Mohammadzadeh is a Fellow of the Iranian Elite Academy. He is co-founder and CEO of Farda-Negar co., Tabriz, Iran, which ranked as a knowledge-based enterprise. The main discipline of the firm is heat treatment and surface modification services.

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 doctorates.

Nushin Salimi is a Ph.D. student in the Department of Materials Engineering at Science Research Branch of Islamic Azad University, Tehran, Iran. She obtained her M.Sc degree in Materials Engineering (Powder Metallurgy) at Sahand University of Technology in 2016, and her B.Sc degree in Materials Engineering (industrial metallurgy) at Tabriz University in 2011.