Influence of powder size distribution and powder density distribution on the final shape of PM HIP-ed components
Final Report Abstract
The most important scientific works of this project are: (I) Development of the constitutive equation for powder material (316L) to describe the physical mechanisms occurring during the HIP process in more detail. A combined model following the continuum approach, which takes into account densification due to plastic and viscoplastic mechanisms during HIP processes, is implemented in the UMAT user subroutine for ABAQUS. (II) Conducting all experiments to determine thermal and mechanical properties of the powder (316L) as well as capsule material (304). Furthermore, rheological, plastic, viscoplastic parameters for the simulation model are experimentally determined. This work is really important because the parameters are either not available or considerably different in the literature. (III) Development of a methodology to determine the initial powder distribution inside a capsule before submitting it to HIP. The results from experiment (Image Analysis) are included into a FEM model as initial conditions. (IV) Analyze the influence of the initial powder distribution inside capsules prior to HIP on the final shape of HIP-ed capsules via simulation and experimental work. The results of this project prove that the initial relative density is not homogeneous and a density gradient is one reason for the distortion of HIP-ed capsules. Further work should continue for bigger and more complex components. (V) Analyze the influence of powder size and powder size distribution on the densification process. In this part, different powders which have different powder sizes and size distributions are used to find the influence of these parameters on the powder distribution after the pre-consolidation process, as well as its influence on the densification process and final shape of HIP-ed components.
Publications
- “Inclusion of initial powder distribution in FEM modeling of near-net-shape PM hot isostatic pressed components”; J. Powder Metallurgy, Vol.57, No.4, 2014, pp.295-303
Van Nguyen C.; Bezold A.; Broeckmann C.
(See online at https://doi.org/10.1179/1743290114Y.0000000087) - “Anisotropic shrinkage during HIP of encapsulated powder”; J. Mater. Proc. Tech. Vol.226, December 2015, pp.134-145
Van Nguyen C.; Bezold A.; Broeckmann C.
(See online at https://doi.org/10.1016/j.jmatprotec.2015.06.037) - “Final shape prediction of PM HIP components by numerical simulation”; cfi/Ber. DKG, Vol. 92, No. 9, 2015, pp.E1-E4
Van Nguyen C.; Bezold A.; Broeckmann C.
- “A comparative study of different sintering models for Al2O3”; Special Issue: Microstructural Design and Control of Ceramics through Sintering, Journal of the Ceramic Society of Japan. 124 (2016) 4, p. 301-312
C. Van Nguyen, S. K. Sistla, S. v. Kempen, N. A. Giang, A. Bezold, C. Broeckmann, and F.Lange
(See online at https://doi.org/10.2109/jcersj2.15257)
