Institute of Fundamental Technological Research

The mechanical response of interpenetrating co-continuous composite Al-Si12/SiC3D was described for uniaxial tension
and compression. The internal structure of the IPC was examined by optical microscopy and micro-CT. The apparent density and
Young’s modulus were assessed theoretically and experimentally. Uniaxial tensile tests were performed using the prismatic samples
of dimensions 1 mm × 2 mm × 30 mm. Cylindrical samples of diameters ϕ = 5 mm and height h = 10 mm were subjected to quasistatic uniaxial compressive loading. During tests, the side surfaces of the specimen were observed using a digital image correlation system (DIC) to find strain fields and to monitor the surface cracks development in the complex internal microstructure of the IPC.
The analyzed two-phase ICP was manufactured using ceramic foam SiC infiltrated by alloy Al-Si12. This material finds application
in cosmic, airplane, or automobile industries, due to their excellent tribological, heat distribution, and ballistic properties.
Obtained results show different modes of microcracking and fracture of cylindrical and prismatic samples. They indicate the
substantial influence of the ceramic skeleton on the behavior of the IPC under uniaxial states of loading. Different modes of damage related to the tension or compression loading were described in detail. The results can find application in the designing process of modern co-continuous IPCs and further development of the numerical models of degradation processes.

Co-continuous composite, Al-Si12/SiC , interpenetrating composite, tension and compression tests

Ceramic composites are used in such industries as the armaments industry, aviation, automotive, nuclear power, and space exploration. In several areas, they stand as the source of technological progress. The material is often subjected to extreme loads, such as variable dynamic loads and high temperatures. Peridynamics is a non-local, meshless, quite recently formulated method of stress analysis. The methods appear to be useful in the analysis of brittle materials. In the paper, an impact model of an Al2O3/ZrO2 thin plate is investigated. A brittle damage model is used for both phases of the composite. The attention is focused on damage initiation and distribution in the impacting sample.

brittle composites, Al2O3/ZrO2, impact, peridynamics

Quasi-static degradation of brittle composites exhibits different mechanical responses under uniaxial tension and uniaxial compression. In this paper, we analysed cracking processes and failure under quasi-static loading of 2 phase ceramic material made of alumina and zirconia mixture, subjected to tension and compression. Constitutive modelling of two-phase ceramic composites obeys description of (1) elastic deformations of initially porous material, (2) limited plasticity and (3) cracks initiation and propagation. Modelling of polycrystalline ceramics at the mesoscopic level under mechanical loading is related to the analysis of a set of grains, which create a so-called Representative Volume Element (RVE). The basic elements of the defect structure inside polycrystal are: micro- and meso-cracks, kinked and wing cracks. To get the macroscopic response of the material one can calculate averaged values of stress and strain over the RSE with the application of an analytical approach. The dynamic degradation process was illustrated for 2 phase ceramic matrix composite and cermet, which was subjected to short compressive impulse. The pulse duration was 10-7s and the applied pressure level - 480 MPa. In the proposed, more advanced finite element formulation of the cermet behaviour is was necessary to take into account the following data and phenomena revealing inside of the RVE: (1) spatial distribution of the cermet constituents, (2) system of grain boundaries/binder interfaces modelled by interface elements, (3) rotation of brittle grains. The cermet response due to pulse loading is significantly different in comparison to the quasi-static behaviour, i.e. the stress distributions and microcracking processes are quite different.

cermets, dynamic behaviour, brittle cracking

The paper presents the modelling of a ceramic foam that works as a skeleton of Interpenetrating Phase Composites (IPCs) before filling the preforms. The preforms are made of SiC or Al2O3. A dynamic analysis of the impact of such skeletons against the rigid surface is performed. The results of the quasi-static analysis will serve as a reference to the dynamic analyses. The analysis of the IPCs skeleton is performed due to evaluation of the role of the skeleton in a final product that is the filled IPCs.

interpenetrating phase composites, metal-matrix composites, ceramic skeleton, peridynamics, high-performance computing

W pracy przedstawiono badania eksperymentalne kompozytów ceramicznych infiltrowanych poddanych działaniu obciążeń mechanicznych. Rozpatrywany typ kompozytów wytwarzany jest z pianki ceramicznej typu SiC, która wypełniona jest stopem AlSi. Ten typ zaawansowanego kompozytu jest stosowany w przemyśłe kosmicznym, lotniczym i samochodowym.
Przeprowadzono obserwacje mikroskopowe struktury badanych kompozytów oraz pianki ceramicznej, wykonano skany micro-CT.
Odpowiedź na obciążenia dynamiczne zbadano prętem Hopkinsona używając próbek krępych.
Uzyskane wyniki pokazują postacie zniszczenia próbek cylindrycznych i beleczek. Wskazują one na istotny wpływ szkieletu ceramicznego na zachowanie kompozytu.

The experimental testing of interpenetrating composite was presented for uniaxial compression or tension. The analysed composite was manufactured using SiC ceramic foaminfiltrated by an alloy of AlSi. This type of composites is used in cosmic, aerospace, or automotive idustries.
The response of the rested material waas investigated using stocky samples in the Hopkinson bar device.
The obtained results exhibit different modes of fracture of cylindrical and beam samples. They indicate the substantial influence of the ceramic skeleton on the behaviour of the composite under the dynamic loading.

Kompozyty metalowo ceramiczne, kompozyty infiltrowane, skany CT, pręt Hopkinsona, dynamika, pękanie zniszczenie / Metal matrix composites, infiltrated composites, CT scanning, Hopkinson bar, dynamics, fracture, failure

Quasi-static degradation of brittle composites exhibits different mechanical response under uniaxial tension and uniaxial compression. In this paper we analysed cracking processes and failure under quasi-static loading of 2 phase ceramic material made of alumina and zirconia mixture, subjected to tension and compression. Constitutive modelling of two phase ceramic composites obeys description of: (1) elastic deformations of initially porous material, (2) limited plasticity and (3) cracks initiation and propagation. Modelling of polycrystalline ceramics at mesoscopic level under mechanical loading is related to analysis of a set of grains, which create so called Representative Volume Element (RVE). The basic elements of the defect structure inside polycrystal are: micro- and meso-cracks, kinked and wing cracks. To get macroscopic response of the material one can calculate averaged values of stress and strain over the RSE with application of analytical approach. Dynamic degradation process was illustrated for 2 phase ceramic matix composite and cermet, which was subjected to short compressive impulse.
The pulse duration was 10-7s and the applied pressure level - 480 MPa. In the proposed more advanced nite elements formulation of the cermet behaviour is was necessary to take into account the following data and phenomena revealing inside of the RVE: (1) spatial distribution of the cermet constituents, (2) system of grain boundaries/binder interfaces modelled by interface elemnets, (3) rotation of brittle grains. The cermet response due to pulse loading is signifcantly different in comparison to the quasistatic behaviour, i.e. the stress distributions and microcracking processes are quite different.

brittle composites, damage, quasi-static behaviour, dynamics, RVE

The ceramic composites Al2O3/ZrO2 are used for different kind of implants since they are nontoxic and nonallergic [1]. The composites of different composition of both compounds are obtained by sintering at the temperature 1600◦C. The amount of zirconia in the composite is normally up to 30% volume. The investigation of such properties like Youngs modulus, toughness and flexural strength is presented in [2]. The properties of ZrO2 compound with stabilization of Y2O3 are described in [3].

Al2O3/Zr02, composite compositions, impact, peridynamics