Investigation of material interfaces obtained by two- component-micro- MIM and Co-sintering

In this study, 316L and 17-4PH feedstocks were made to manufacture ferromagnetic / nonmagnetic material joints. Micro tensile specimens were moulded using a 'sequential' and a 'simultaneous' injection moulding route. In the sequential process, the feedstocks were injected into the mould one after another, whereas in the simultaneous process, injection of both feedstocks was carried out at the same time. For the samples obtained, sintering parameters were varied to obtain optimum co- sintering results. Characterisation of the microstructure and diffusion zones at the interfaces is done by optical microscopy and SEM along with micro hardness measurements, EDX linescans and micro tensile tests. Manufacturing of 316L / 17-4PH micro tensile specimens was successfully carried out for both processing routes investigated. While the sequential injection route lead to precisely positionable, straight interfaces, better interdiffusion of the materials was detected in the simultaneously injected samples. The latter material also showed better mechanical strength for both sintering cycles tested. For the transfer of the 2C-micro-MIM technology to potential technological applications, it is desirable to combine a precise positioning with optimum mechanical bonding of the materials. This is why further work is aiming at the optimisation of injection moulding and debinding parameters to obtain precise positioning and crack-free interfaces in co-sintered micro parts.