Simultaneous Spark Plasma Sintering of Multiple Complex Shapes

TL;DR

This paper presents a novel SPS method enabling the simultaneous sintering of multiple complex-shaped nickel parts with homogeneous microstructure, using a controllable interface and energy-efficient configuration.

Contribution

A new controllable interface technique and energy-efficient SPS setup for concurrent sintering of multiple complex parts are introduced.

Findings

Successful sintering of two nickel gear shapes simultaneously

Homogeneous microstructure achieved in fabricated gears

ETM simulation validated process stability and thermal confinement

Abstract

This work addresses the two great challenges of the spark plasma sintering (SPS) process: the sintering of complex shapes and the simultaneous production of multiple parts. A new controllable interface method is employed to concurrently consolidate two nickel gear shapes by SPS. A graphite deformable sub-mold is specifically designed for the mutual densification of the both complex parts in a unique 40 mm powder deformation space. An energy efficient SPS configuration is developed to allow the sintering of a large-scale powder assembly under electric current lower than 900 A. The stability of the developed process is studied by electro-thermal-mechanical (ETM) simulation. The ETM simulation reveals that homogeneous densification conditions can be attained by inserting an alumina powder at the sample/punches interfaces enabling the energy efficient heating and the thermal confinement of the nickel powder. Finally, the feasibility of the fabrication of the two near net shape gears with a very homogeneous microstructure is demonstrated.