|Natalia Sobczak, Rafał Nowak, Alberto Passerone, Fabrizzio Valenza, Maria L. Muolo, Lucyna Jaworska, Fabrizio Barberis, Marco Capurro|
The wetting behavior of Ni on a HfB2/Ta assembly was examined in vacuum using dense HfB2 (99.5% purity) produced, without sintering aids, by HP-HT at 7 GPa. The real-time imaging by a high resolution digital camera and precise temperature control demonstrated solid-state Ni/HfB2 interaction resulting in metal contact melting at ~1300ºC. Ongoing heating, the in situ formed Ni-B alloy wets, spreads over HfB2 and penetrates the HfB2/Ta capillary interface to form a joint of complex graded structure and good bonding.
Keywords: wetting, joining, hafnium boride, tantalum, nickel,
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Zbigniew Stefański, Małgorzata Warmuzek, Łukasz Boroń
The article presents the most important results of the research, development and implementation studies carried out under one of the Target Projects as a result of cooperation between the CERTECH Technical and Commercial Enterprise at Niedomice (manufacturer of materials for foundry industry) and Foundry Research Institute in Cracow. The aim of the project was development of innovative technology and start up of the production of "modified bentonite" used in production of steel castings characterised by very high surface quality. The results of investigations regarding possible use of carbon additives to moulding sands for the manufacture of steel castings were presented and discussed, including the effect of these additives on casting surface quality, especially on casting skin in terms of its possible carburising. Studies were described, the final outcome of which was the development of "modified bentonite", the development of its manufacturing technology, and finally the start up of production.
Keywords: bentonite moulding sands, steel castings, coal dust, coal dust substitutes, casting surface quality, casting skin,
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Andrzej Gazda, Zbigniew Górny, Stanisława Kluska-Nawarecka, Krzysztof Saja, Małgorzata Warmuzek
The article discusses problems related with the evaluation of the effect of modification and multivariant heat treatment on mechanical properties of CuAl10Fe3Mn2 aluminium bronze. The evaluation was based on the results of mechanical tests (Rm, Rp0,2, A, Z), hardness measurements (HB), calorimetric and dilatometric examinations, and metallography. The results were analysed by modern methods of the statistical analysis of an inverse problem using fuzzy logic, combined with graphical interpretation of surface charts. Interesting results were obtained, and they enable control of mechanical properties of CuAl10Fe3Mn2 alloy, depending on the type of the carried out heat treatment.
Keywords: modification of copper alloys, copper alloys, heat treatment,
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