Partner: Thomas Schubert

Fraunhofer Institut für Fertigungstechnik und Angewandte Materialforschung (DE)

Recent publications
1.Węglewski W., Basista M., Manescu A., Chmielewski M., Pietrzak K., Schubert Th., Effect of grain size on thermal residual stresses and damage in sintered chromium–alumina composites: Measurement and modeling, COMPOSITES PART B-ENGINEERING, ISSN: 1359-8368, DOI: 10.1016/j.compositesb.2014.06.027, Vol.67, pp.119-124, 2014
Abstract:

In this paper we present the results of experimental measurements and numerical modeling of the effect of particle size on the residual thermal stresses arising in sintered metal–matrix composites after cooling down from the fabrication temperature. On example of novel Cr(Re)/Al2O3 composites processed by (i) spark plasma sintering and (ii) hot pressing the residual thermal stresses are measured by neutron diffraction technique and determined by a FEM model based on micro-CT scans of the material microstructure. Then numerical model of microcracking induced by residual stresses is applied to predict the effective Young modulus of the damaged composite. Comparison of the numerical results with the measured data of the residual stresses and Young’s modulus is presented and fairly good agreement is noted.

Keywords:

Metal–matrix composites (MMC), Residual/internal stress, Finite element analysis (FEA), Sintering

Affiliations:
Węglewski W.-IPPT PAN
Basista M.-IPPT PAN
Manescu A.-Universita degli Studi di Ancona (IT)
Chmielewski M.-Institute of Electronic Materials Technology (PL)
Pietrzak K.-other affiliation
Schubert Th.-Fraunhofer Institut für Fertigungstechnik und Angewandte Materialforschung (DE)
2.Węglewski W., Bochenek K., Basista M., Schubert Th., Jehring U., Litniewski J., Mackiewicz S., Comparative assessment of Young’s modulus measurements of metal-ceramic composites using mechanical and non-destructive tests and micro-CT based computational modeling, COMPUTATIONAL MATERIALS SCIENCE, ISSN: 0927-0256, DOI: 10.1016/j.commatsci.2013.04.007, Vol.77, pp.19-30, 2013
Abstract:

It is commonly known that the available non-destructive and mechanical methods of the Young modulus measurement yield different results. This paper presents comparison of the results of experimental determination and numerical modeling of the Young modulus of Cr–Al2O3–Re composites (MMC) processed by a powder metallurgical method (SPS). In the computational model a finite element analysis is combined with images of the real material microstructure obtained from micro-computed tomography (micro-CT). Experimental measurements were carried out by four testing methods: three-point bending, resonance frequency damping analysis (RFDA), ultrasonic pulse-echo technique, and scanning acoustic microscopy. The paper also addresses the issue which of the four experimental methods at hand gives results closest to the theoretical predictions of the micro-CT based FEM model.

Keywords:

Finite element analysis (FEA), Micro-CT based FE model, Metal matrix composites, Elastic modulus, Mechanical and nondestructive techniques

Affiliations:
Węglewski W.-IPPT PAN
Bochenek K.-IPPT PAN
Basista M.-IPPT PAN
Schubert Th.-Fraunhofer Institut für Fertigungstechnik und Angewandte Materialforschung (DE)
Jehring U.-Fraunhofer Institut für Fertigungstechnik und Angewandte Materialforschung (DE)
Litniewski J.-IPPT PAN
Mackiewicz S.-IPPT PAN