Spark plasma sintering and complex shapes: The deformed interfaces approach

Abstract

OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible. a b s t r a c tOver the last few decades, the SPS technique has proven its benefits in terms of microstructure control, reduction of cycling time and a general stability of the results. However, to overcome the so-called "valley of death" between fundamental research and successful industrialization, the next step is to prove the ability of this technology to perform the total densification of highly complex shape samples. The elaboration of complex shapes with die compaction processes often present densification inhomogeneity because of the thickness differences of the sample. In this paper, we present a method to solve this problem with an approach we called the "deformed interfaces method" that uses sacrificial materials. This method can be generalized to all the pressure assisted sintering techniques and allow a complete densification whatever the shape complexity of the part. This method is tested with different materials (Al, CoNiCrAlY, PMMA, Al 2 O 3 , 4Y-ZrO 2 ) and shapes. To prove the effectiveness of this method on very high complex shapes, a 98% dense turbine blade shape has been made.

FAST-forge of Diffusion Bonded Dissimilar Titanium Alloys: A Novel Hybrid Processing Approach for Next Generation Near-Net Shape Components

“…When compared to conventional powder processing and sintering methods, FAST is advantageous due to an electrical current, which has been shown to provide faster heating rates and consolidation compared to conventional sintering [16,17]. FAST has been demonstrated to be an effective sintering route for complex shapes, most notably a novel deformable interface approach produced fully dense CoNiCrAlY turbine blades [18]. Furthermore, FAST-forge [5] and FAST-DB [19] processing routes have been developed, primarily to provide an alternative route to produce titanium components from particulate feedstocks.…”

Spark Plasma Sintering of Titanium Aluminides: A Progress Review on Processing, Structure-Property Relations, Alloy Development and Challenges

“…To date, various models have been employed in SPS to overcome those, as mentioned earlier. These include modified punch designs [68], controlling punch displacement through the usage of sacrificial materials [69], deformed interface approach [70], finite element method (FEM) [67,71], and the controllable interface approach [66].…”

“…The detailed process steps for the deformed interfaces method are shown in Figure 7, and consists of the reproduction of porous assembly materials, densification of the assembly materials and sacrificial parts removal. Successful implementation of this method includes a 98% densification of a highly complex CoNiCrAlY alloy turbine blade developed by Manière et al [70]. Finally, the recent controllable interface approach combines the adjustable interface thermal/electrical fluxes and the DEFORMINT approach.…”

How to overcome the main challenges of SPS technology: Reproducibility, multi-samples and elaboration of complex shapes

“…The powder of the desired material is thus introduced in the extended cavity defined by the assembly of counter-parts [69,70]. Thus, during the sintering cycle, the part reaches its full density, while the surrounding media compacts not necessarily to full density.…”