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

摘要

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 degrees C, 890 degrees C and in part at 930 degrees 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 degrees C) so that O-shape and X-shape distortions were observed at high and low green density samples, respectively.