With series production of aluminium foams according to the Fraunhofer process a reality, further improvement of structural homogeneity has gained interest. Since this characteristic is strongly influenced by blowing agent decomposition, means to adapt the latter have been investigated: The paper concentrates on thermal treatment of TiH2, comparing effects induced by treatment time, temperature and atmosphere variation. Structural characteristics of AlSi7 foams using TiH2 variants as foaming agent are evaluated.

No abstract

The advantages advanced pore morphology (APM) and a reduction in production complexity are discussed. These two aspects are key to low-cost PM manufacturing of aluminum foam parts. APM approach is based on the separation of the two main steps of the powder metallurgical process for production of metal foam parts, namely foam expansion and part shaping. APM metal foam parts consist of small-volume foam elements joined to each other in a separate process step. It is pointed that with a reduced part price, existing markets could be served with low-cost but high-quality metal foam parts

No abstract

A model for the single-edge notched-beam (SENB) test is presented which allows the load-displacement curve of fiberreinforced ceramic-matrix composite (CMC) specimens to be calculated using the crack-opening function. This function considers the effects of the main parameters of the composite components that govern the fracture of the composite (e.g., fiber strength and interfacial properties). Then, in an experimental study, the SENB curves of an oxide-oxide composite are measured in the as-processed state and after exposure at elevated temperatures. Comparison between the measured and calculated SENB curves indicates that the characteristic loss of the maximum load in the SENB curves due to the annealing is caused by the corresponding reduction of the in situ fiber strength. This method then is proven to be an excellent tool to evaluate the actual fiber strength in CMCs, which is, otherwise, barely measurable. It will be shown that the SENB test is very much qualified for a proper investigation of the relationship between in situ fiber strength and composite strength (the maximum SENB load), because of the limited influence of other parameters (Weibull modulus of the fiber strength and the friction coefficient) on the maximum SENB load.