M. Watzlaw's scientific contributions

Dieses Manuskript beschreibt das Reibschweißen der intermetallischen γ-TiAl-Basislegierung Ti-47Al-3.5(Mn+Cr+Nb)-0.8(B+Si) im heißisostatisch gepressten Feingusszustand. Die mechanischen und mikrostrukturellen Eigenschaften der γ-TiAl-Reibschweißverbindung werden untersucht und dargestellt. Es wird gezeigt, dass die Reibschweißverbindung sowohl bei Raumtemperatur als auch bei 700 °C im Wesentlichen durch die Grundwerkstoffeigenschaften der Feingusslegierung Ti-47Al-3.5(Mn+Cr+Nb)-0.8(B+Si) bestimmt wird. Der Einfluss der Reibschweißparameter auf die Mikrostruktur und damit auf die lokalen Festigkeitseigenschaften wird diskutiert. Microstructure and mechanical properties of friction welded γ-TiAl based alloy Ti-47Al-3.5(Mn+Cr+Nb)-0.8(B+Si) in investment cast condition. This paper describes properties of joints produced by friction welding of the intermetallic γ-TiAl based alloy Ti-47Al-3.5(Mn+Cr+Nb)-0.8(B+Si) in investment cast and hot-isostatically pressed condition. The effect of friction welding parameters on microstructure and local properties are examined and discussed. It is found that the properties of the joint are essentially affected by properties of as-cast Ti-47Al-3.5(Mn+Cr+Nb)-0.8(B+Si) base material, both at room temperature and 700 °C.

Similar joints made of a TiAl alloy and a Ti6Al4V alloy were to be manufactured by means of friction welding. In this respect, the following parameters were varied on the friction welding machine: the upsetting pressure, the upsetting duration, the friction pressure, the friction path, the process duration and the rotational speed. It was shown that the relatively ductile Ti6Al4V alloy is friction-weldable within a wide parameter range. On the other hand, the less ductile TiAl alloy benefits from measures such as homogenisation annealing and preparation of the surfaces by means of grinding and lapping. Furthermore, it is necessary to choose a higher upsetting pressure, upsetting duration, friction pressure and friction path than with the Ti6Al4V alloy.