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This paper presents a new apparatus to measure elastic properties and internal friction of materials. The apparatus excites the test specimen by a light mechanical impact (impulse excitation) and performs a software-based analysis of the resulting vibration. The resonant frequencies fr of the test object are determined and, in the case of isotropic and regular shaped specimens, the elastic moduli are calculated. The internal friction value (Q−1) is determined for each fr as Q−1=k/(πfr) with k the exponential decay parameter of the vibration component of frequency fr. A furnace was designed and equipped with automated impulse excitation and vibration detection devices, thus allowing computer-controlled measurements at temperatures up to 1750 °C. The precision of the measured fr depends on the size and stiffness of the specimen, and varies from the order of 10−3 (that is ±1 Hz at 1 kHz) in soft, high damping materials or light specimens, to values as precise as 10−5 (that is ±0.1 Hz at 10 kHz) in larger or stiffer specimens. The highly reproducible Q−1 measurements are accurate whenever the relation Q−1=k/(πfr) holds. The precision of the Q−1 measurement depends on the suspension or support of the specimen, and on the specimen size. Since external energy losses are relatively smaller for larger specimens, the lower limit of measurable Q−1 extends from 10−3 for small specimens (for example <1 g) down to 10−5 with increasing specimen size. High temperature tests have shown that Q−1 can be monitored up to values of about 0.1.

High temperature flexural strength of ZrB2–20 vol% SiC ceramics (ZS) up to 1600°C in high purity argon atmosphere was significantly improved by adding 5 vol% WC, but degraded when 5 vol% ZrC was added. ZrB2–20SiC–5WC ceramic (ZSW) has a very high strength (mean ± SD) of 675 ± 33 MPa at 1600°C, and also an elastic and transgranular fracture mode was observed. According to the analysis of the fracture modes and crack origins in ZSW ceramics, the improvement in strength above 1000°C was attributed to the removal of the oxide impurities from grain boundaries.

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Shaped metal deposition is a novel technique to build near net-shape components layer by layer by tungsten inert gas welding. Especially for complex shapes and small quantities, this technique can significantly lower the production cost of components by reducing the buy-to-fly ratio and lead time for production, diminishing final machining and preventing scrap. Tensile testing of Ti-6Al-4V components fabricated by shaped metal deposition shows that the mechanical properties are competitive to material fabricated by conventional techniques. The ultimate tensile strength is between 936 and 1014 MPa, depending on the orientation and location. Tensile testing vertical to the deposition layers reveals ductility between 14 and 21%, whereas testing parallel to the layers gives a ductility between 6 and 11%. Ultimate tensile strength and ductility are inversely related. Heat treatment within the α + β phase field does not change the mechanical properties, but heat treatment within the β phase field increases the ultimate tensile strength and decreases the ductility. The differences in ultimate tensile strength and ductility can be related to the α lath size and orientation of the elongated, prior β grains. The micro-hardness and Young's modulus are similar to conventional Ti-6Al-4V with low oxygen content.

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