Residual Stresses in Novel Metal/ceramic Composites Exhibiting a Lamellar Microstructure
نویسندگان
چکیده
The aim of this study is to analyze the mechanics of a new class of metal/ceramic composite on a mesoscopic length scale. These composites are produced by melt infiltration of porous ceramic preforms produced by freeze-casting and subsequent sintering. This production route has a high application potential since it offers a cost-effective way to obtain composites with ceramic content in the range 30-70 vol%. The as-produced material exhibits a hierarchical domain structure with each domain composed of alternating layers of metallic and ceramic lamellae. Residual stresses present in all phases of the composite produced by infiltrating alumina preforms with a eutectic aluminium-silicon alloy have been measured. Integral as well as spatially resolved measurements were carried out on single domain samples at the high-energy, energy-dispersive diffraction (EDDI) beamline at the synchrotron radiation source BESSY (Berlin, Germany). Results show that strongly fluctuating residual stresses are introduced by the production process, which can be rationalized taking into account the thermal expansion mismatch of alloy and preform.
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