Pressureless Sintering and Spark-Plasma Sintering of Fe-TiC Composite Powders

Two sintering methods of a pressureless sintering and a spark-plasma sintering are tested to densify the Fe-TiC composite powders which are fabricated by high-energy ball-milling. A powder mixture of Fe and TiC is prepared in a planetary ball mill at a rotation speed of 500 rpm for 1h. Pressureless sintering is performed at 1100, 1200 and for 1-3 hours in a tube furnace under flowing argon gas atmosphere. Spark-plasma sintering is carried out under the following condition: sintering temperature of , soaking time of 10 min, sintering pressure of 50 MPa, heating rate of , and in a vacuum of 0.1 Pa. The curves of shrinkage and its derivative (shrinkage rate) are obtained from the data stored automatically during sintering process. The densification behaviors are investigated from the observation of fracture surface and cross-section of the sintered compacts. The pressureless-sintered powder compacts show incomplete densification with a relative denstiy of 86.1% after sintering at for 3h. Spark-plasma sintering at for 10 min exhibits nearly complete densification of 98.6% relative density under the sintering pressure of 50 MPa.