Sintering behavior of 316L stainless steel micro–nanopowder compact fabricated by powder injection molding

• Sintering behavior of PIMed 316L stainless steel micro–nanopowder is studied.
• Microstructure development during heat-up and isothermal sintering is observed.
• Enhanced densification can be achieved by addition of nanopowders.
• Nanopowders suppress the growth of the micropowders during full densification.
• PIM parts with full density and fine microstructure can be fabricated.

The densification and grain growth behavior of powder injection molded 316L stainless steel micro–nanopowder were investigated in terms of microstructural development. The sintered density of the micro–nanopowder sample increased remarkably in the temperature range of 1000 to 1100 °C due to the sintering effect of nanopowders which increased the number of grain boundaries acting as high material transport path. A near full density of 98% TD was obtained after sintering at 1100 °C for 5 h with the average grain size less than 10 μm, indicating that there was no drastic grain growth. The presence of nanopowders in micro–nanopowder played decisive role in the entire sintering process by enhancing densification but suppressing grain growth. These effects open up the possibility of using micro–nanopowder feedstock to control the sintering behavior of powder injection molding products with full density and fine microstructure.

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