Influence of impact on the mechanical behaviour of a cast and a forged gamma based TiAl alloy

The influence of impact on the mechanical behaviour of a cast TNBV3B TiAl-alloy and a forged TNBV3B TiAl-alloy with a 50% higher strength has been investigated, Impact tests are performed and the caused damage has been evaluated as a function of the impact speed and the particle weight (the impact energy) in relation to the specimen thickness and location of the impact. Impact near the specimen edge produces a severer damage as an impact in the centre. This is shown with the aid of residual strength experiments. The residual strength could be described on the basis of a linear elastic fracture mechanics analysis and an average fracture toughness of 16 Wa(m)(1/2) for the cast alloy.