ADDITIVE LAYER MANUFACTURING OF TI-6AL-4V AND SCALMALLOYRP: FATIGUE AND FRACUTRE

摘要

Additive Manufacturing is increasingly considered for manufacturing high quality aerospace parts. Therefore it is essential to cover the full range of material characterisations. Today this characterisation is at an early stage especially regarding fatigue loads. Only few data are available. Therefore the paper covers first insights in mechanical behaviour of additive manufactured Ti-6Al-4V more particularly: static strengths, fracture toughness and high cycle fatigue behaviour. For comparison reasons high cycle fatigue behaviour of ScalmalloyRP is investigated. The prediction of the effect of defects (e.g. porosity, un-melted spots or lack of fusion) on the fatigue behaviour based on a fracture mechanical approach using the da/dN - ΔK curve is discussed for Ti-6Al-4V. The investigated additive manufacturing techniques are based on powder and wire processes. Their corresponding energy source is either a laser or electron beam. It can be shown that the high cycle fatigue properties are dominated by defects in a negative way while simulation seems to be a suitable approach for "post-diction" of powder bed electron beam S-N curves.