抄録
A mass of metal powder is characterized by powder particles and the voids between these particles. The variables of the porosity in metal powder compacts are discussed and analyzed, and the rate of densification during sintering is expressed in an equation consisting exclusively of various functions of porosity. The changes of porosity during the sintering process are discussed. It is shown that the differences between sintering of pressure-compacted, deformed powder particles and undeformed, loose powders are due to the variation in the pore structure; the rate of densification during sintering of undeformed powder particles is considerably greater than that of particles deformed by pressure. Pores in metal powder compacts affect the grain boundary movement, as solid inclusions do. The bond between a grain boundary and a void depends on the pore shape. Before spheroidization of the voids, the grain boundaries stick to the voids; after spheroidization, the grain boundaries move away. Oriented porosity may cause oriented grain structure.
