Iron powder-based graded products sintered by conventional method and by SPS

• Method of filling the die with powder to create graded products.
• Comparison of conventional sintering with SPS method.
• Increased amount of pearlitic–bainitic structure by SPS method.
• Similar density, lower shrinkage and higher hardness given by SPS method.
• The most favourable structure obtained by SPS at 1120 °C and 10 min duration.

Iron powder-based graded products sintered by various methods were evaluated. Cylindrical samples were made from the Distaloy SE powder with different carbon content in the outer layer and core. Between the outer layer and the core, a transition zone was formed as a result of the application of special die filling technique providing mixing of the two powder compositions. The applied technique allowed the transition zone to be formed not only by the diffusion process during sintering, but earlier at the stage of product shaping. Two methods of sintering after compaction were tested, i.e. pressureless sintering and pressure-aided sintering using pulsed current, known as Spark Plasma Sintering (SPS).

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