Additive manufacturing of ceramics and cermets: present status and future perspectives

Abstract

At present, fabrication of ceramics using AM-based techniques mainly suffers from two primary limitations, viz: (i) low density and (ii) poor mechanical properties of the finished components. It is worth mentioning that the present state of research in the avenue of AMbased ceramics is focussed mainly on fabricating ceramic and cermet components with enhanced densities and improved mechanical properties. However, to the best of the authors' knowledge, not much is known about the microstructure evolution and its correlation with the mechanical properties of the finished parts. Addressing the aforementioned avenue is highly essential for understanding the utilisation of these components for structural applications. To this end, the present review article is aimed to address the future perspectives in this avenue has been provided with a special emphasis on the need to establish a systematic structureproperty correlation in these materials.

A Brief Discussion on High-Entropy Alloys vs Compositionally Complex Alloys

“…However, in spite of all challenges, HEAs are found to possess excellent novel properties such as high specific strength, superconductivity, superparamagnetism, excellent mechanical properties at elevated temperature, excellent ductility and fracture toughness at cryogenic temperature [4] . For instance, HEAs, as light as Al, but stronger than Metallic glasses, have been investigated to be useful for transport and energy sectors where "lightweight" materials have a huge demand due to reduction in fuel consumption and thus, minimising the energy requirements [16][17][18][19][20] . Refractory HEAs find application in high-temperature applications like gas turbines, rocket nozzles, nuclear construction e.t.c whereas, Lightweight refractory HEAs find applications in aerospace applications like re-entry nosecones.…”

Additive manufacturing of ceramics: Present status and future perspectives

“…Besides, a number of defects, particularly ranging from 2-D (surface) defects (such as grain boundaries, interphase boundaries etc.) to various 3D (volume) defects (mainly, porosity) are associated with AM based ceramic parts [1], which require extensive microstructural investigations to be overcome. Moreover, the intrinsic staircase effect associated with AM techniques leads to notch sensitivity issues of final ceramic parts [2].…”

“…necessitating the viscous ceramic paste to be free of large aggregates. In addition, during debinding of green ceramic parts made of powder injection molding (PIM), broad temperature range of binder decomposition leading to an easy escape of the evaporated gas phase from the binder has been reported to minimise the extent of cracking in the debinded parts [1]. In this regard, slow decomposition of the binder has also been reported to be beneficial for retention of the final part shape [6]- [8].…”

Advanced Materials for Biomechanical Applications

“…Inspite of the tremendous advantage offered by AM techniques in addressing design complexities in a wide range of materials ranging from metallic materials to Functionally Graded Materials (FGM) [2], [12], the primary challenge still remains in obtaining 'real, robust and functional' objects of engineering interest [3], [13], [14]. Moreover, the other challenges include: (i) size limitations [1], [15], (ii) quality consistency [16], (iii) scaling issues [17], [18] and (iv) high material cost [16], [18], [19].…”