Frank Palm

Mechanical Properties of Additive Manufactured Ti-6Al-4V Using Wire and Powder Based Processes

Since 1986 several techniques of building up geometries layer by layer have been developed and successfully commercialized under numerous trade names. Today, not only prototypes are realized by these techniques, but serial production parts are envisaged. To achieve this progress, the development activities have to focus on the reliability and output material quality. Particularly for aerospace applications, the material quality is an all-dominant factor. In this paper, an electron beam based powder-bed process and a laser based wire-feed process are investigated. Microstructure, chemical composition, static tensile and high cycle fatigue properties of Ti-6Al-4V samples are presented and evaluated from an aerospace application point of view. The static tensile properties resulting from both processes are mostly comparable to properties of cast or wrought material depending on post heat treatment and test direction. Fatigue limits of all samples are similar to those of wrought material. The impurity levels of oxygen, nitrogen, carbon and hydrogen are below the maximum level of plate material (AMS 4911L). The wire-feed process leads to a material with fewer impurities than the powder-bed process.

Investigations of aging behaviour for aluminium powders during an atmosphere simulation of the LBM process

ABSTRACT Additive layer manufacturing (ALM) offers for production of parts and components for aeronautical applications potential cost benefits over conventional manufacturing routes. In particular, powder bed processes offer a high degree of design flexibility while enabling weight reduction due to topological optimisation. The quality and properties of the parts are strongly dependent on the powder quality which, in turn, is influenced by handling and storage of the powder. For this reasons an undefined contamination of atomised powder materials by oxygen and hydrogen has to be avoided. Aluminium-silicon powder was aged under atmosphere of different moistures and temperatures for defined duration. The effect of these environments as well as the effect of vacuum drying on the flowability was investigated. The morphology was evaluated by scanning electron microscope. The chemistry including oxygen content of the powder was measured by inductively coupled plasma optical emission spectrometry and hot fusion analysis.