Additive Manufacturing of Ceramics by Laser Flash Sintering
Abstract
Additive Manufacturing of Ceramics by Laser Flash SinteringWhile additive manufacturing of polymers and metals is becoming increasingly routine, additive manufacturing of ceramics remains challenging. The slow sintering kinetics, high homologous temperatures, large Young~s modulus, poor thermal conductivity and low fracture toughness present particular challenges for layer-by-layer processing. Previous attempts at direct manufacturing of bulk ceramics has resulted in failure due to thermal shock. The proposed research on laser flash sintering (LFS) aims to addresses the two significant challenges of direct additive manufacturing of ceramics: 1) slow sintering kinetics and 2) thermal shock. LFS utilizes a scanning laser along with an electric field to dramatically reduce sintering times and temperatures. In addition, in LFS, fracture is mitigated by limiting the laser flash sinter process to the initial stage of sintering, e.g. neck formation. Because neck formation can be achieved at much lower temperatures and shorter times than densification, and the part has a low Young~s modulus in this regime, thermal shock should be eliminated. The ceramic particles form necks only where the laser heats it sufficiently. These necks between the ceramic powder particles provide sufficient strength to allow separation of the partially sintered powder from the un-sintered powder, thereby defining the shape of the part within the LFS system. A post-scan furnace sintering (conventional or flash sintering) is then used after the parts are removed from the LFS part bed to fully densify the ceramic.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 10, 2018
- Source ID
- N000141812261
Entities
People
- Desiderio Kovar
Organizations
- Office of Naval Research
- United States Navy
- University of Texas at Austin