Microstructure and densification behavior of liquid phase sintered Cu-28Zn prealloyed powder

The present study investigates the effect of sintering temperature on densification behavior and properties of liquid phase sintered Cu-28Zn brass alloy. Microstructural evolution, chemical analysis and mechanical properties measurements have been studied in details. Obtained results allowed to accurately evaluating the sintering characteristic of this alloy. It is especially relevant in sintered samples that exhibits a pronounced variation of microstructure from top to down part of the specimens and consequently graded densification which was due to gravitational effect.</jats:p

The Effect of Transient Liquid Phase on the Joining Process of Aluminum Foam Core Sandwiches

Abstract Despite recent developments in sandwich panels production technology, there are some difficulties in joining core sandwiches. Liquid Phase Sintering is a conventional method to increase the density of powder metallurgy parts. In this paper, we applied LPS as a joining process between Al-foam and Al-metal by using Al-mixture powders with different compositions as the interlayer. At first stage, Al-Zn powder mixture was used and the possibility of this process was investigated. At later stages, we tried to increase the joint bonding strength with different Al-mixture powder compositions. 3-point bending test was applied and by using mathematical relations, bonding strengths were calculated. The highest bonding strength was obtained, about 9 kPa, when Al-Zn-Mg was used as the interlayer. Also energy dispersive spectrometry (EDS) was used to investigate the diffusion of additive elemental powders to Al-mixture powders.</jats:p

An Investigation of Evolutions during Liquid Phase Sintering of Systems with Volatile Components

In this paper, the possibility of elephant foot phenomenon in sintered alloys with volatile components has been studied. To do this, Cu-28Zn brass samples were sintered at the range of 890-970&deg;C for 20 min. The in situ images from brass samples were taken at various sintering conditions. It is concluded that although liquid is pulled down by gravity, but elephant phenomenon was not appeared in these compacts. Instead, the samples were swelled. Chemical composition change and pores coarsening due to zinc evaporation could be considered as the main cause of swelling in brass compacts

Densification and volumetric change during supersolidus liquid phase sintering of prealloyed brass Cu28Zn powder: Modeling and optimization

An investigation has been made to use response surface methodology and central composite rotatable design for modeling and optimizing the effect of sintering variables on densification of prealloyed Cu28Zn brass powder during supersolidus liquid phase sintering. The mathematical equations were derived to predict sintered density, densification parameter, porosity percentage and volumetric change of samples using second order regression analysis. As well as the adequacy of models was evaluated by analysis of variance technique at 95% confidence level. Finally, the influence and interaction of sintering variables, on achieving any desired properties was demonstrated graphically in contour and three dimensional plots. In order to better analyze the samples, microstructure evaluation was carried out. It was concluded that response surface methodology based on central composite rotatable design, is an economical way to obtain arbitrary information with performing the fewest number of experiments in a short period of time