Forming Complex Graded and Homogeneous Components by Joining Simple Presintered Parts of TRIP-Matrix Composite through Powder Forging

Abstract

The ability to fabricate complex graded structures would be a significant step towards the manufacturing of material systems with properties tailored to individual applications. While powder metallurgy has had some success in this regard, it requires that the semi-finished products be exactly similar to the final component. However, it is significantly cheaper to produce simple, semi-finished products and then join them to form complex components with the desired graded structure through powder forging and simultaneous compaction. It is also essential that the graded structure of the semi-finished products is retained during the forming process. In this study, pre-sintered cylindrical semi-finished products consisting of identical homogeneous layers as well as graded components consisting of non-identical homogeneous layers were joined using powder forging at 1100 °C. The microstructures and densities as well as the mechanical properties of the final components were investigated. It was observed that, upon compaction, the components formed solid structures, in which the reinforcing ZrO2 particles were completely integrated within the transformation-induced plasticity steel matrix. Finally, it was confirmed that the graded structure of the semi-finished products was retained in the final components.

Thermodynamic Database Development for the ZrO2-MgO-MnOx System

“…[1] Manganese provides good adhesion bonding between the steel matrix and the Mg-PSZ ceramics. [2,3] On the other hand, manganese is one of the main alloying elements of the steel matrix and can substitute Mg in Mg-PSZ during processing of this metal matrix composite [2,4,5] thus influencing the stability of the Mg-PSZ structure. It was shown that due to Mg diffusion from Mg-PSZ into precipitate sites or the steel matrix the Mg-PSZ was destabilized and transformed into the monoclinic phase, while due to diffusion of Mn into ZrO 2 particles, grains at its boundary remained cubic or tetragonal.…”