Effect of copper nanoparticles on strengthening of iron base P/M parts formed by high velocity compaction

Cu nanopowders were used to improve the performance of iron based alloy products formed by high velocity compaction. Under the condition that Cu powders were remain unchanged as a constant of 1.5%, part or all of Cu micropowders were replaced by Cu nanopowders. Seven kinds of iron-based alloy product samples in which the mass fractions of Cu nanopowders were 0-0.25%, 0.50%-0.75%, 1.00%, 1.25% and 1.50% respectively were prepared by high velocity compaction. The green compacts were sintered at 1150℃ for 2 h subsequently. It is found that the microstructure and performance of the iron base P/M parts is improved and the dimensional accuracy is also effectively controlled with the addition of Cu nanopowders. The tensile strength and hardness of the sintered alloy which contains 0.75% of Cu nanopowders are 720.6 MPa and 94.7 HRB, respectively. The axial and radial shrinkages of the obtained samples are in the ranges of 0.4% to 0.7% and -0.09% to -0.23% respectively when the mass fraction of Cu nanopowders is from 0.25% to 1.50%.