Plansee Group

Additive manufacturing (AM) of metals has undergone rapid technological development over the past 2 decades. While the beginning was strongly influenced by the development of beam-based processes, the sinter-based AM processes have gained more and more diversity and importance for more than 5 years now. This review presents the results of investigations following process developments of selected sinter-based AM processes using elemental powder mixtures to produce WHA parts. The achieved sintering densities, microstructures, purities as well as mechanical properties are compared with the minimum requirements of the current ASTM standard B777 and typical values of the conventional PM route (p/s). Manufactured demonstrators show the advantages and opportunities of the technologies. According to the current state of technical knowledge, a concluding process overview should serve as a decision-making aid for the right choice of technology for the additive manufacturing of WHA products, considering selected criteria as well as the limitations

To date, researchers have not succeeded in producing defect-free tungsten parts using laser powder bed fusion (LPBF), hindering the commercial realization of LPBF W-parts or reducing it to a few non-load-bearing products. Therefore, research on the LPBF production of components free of defects such as cracks and pores is of great interest to the refractory metals scientific community. The occurrence of such defects can be minimized by the selection of optimized LPBF parameters and by reaction-controlled response to process instabilities. This study presents the use of dimensionless numbers to predict the effect of a particular set of LPBF parameters. In addition, this study demonstrates the effectiveness of in-situ pyrometric signals in predicting the LPBF process and lays the foundation for in-situ parameter modification using pyrometric data. Although this approach is only demonstrated on tungsten, it is reasonable to assume that these principles can be applied to other materials.

Molybdenum (Mo) thin films are serving crucial functions in both conventional and next‐generation display applications, including thin film transistor‐ liquid crystal displays (TFT‐LCDs) and emerging Micro‐LED displays. Their widespread adoption in the display industry stems from their exceptional combination of properties: high electrical conductivity, superior thermal stability, and excellent compatibility with glass substrates. These characteristics make Mo thin films particularly suitable for critical TFT components such as gate electrodes, source/drain electrodes, and diffusion barrier layers. Recognizing the fundamental relationship between target microstructure and thin film properties, this study systematically investigates the influence of Mo target characteristics on sputtering behavior and resultant film properties. Through precise control of grain size and crystallographic texture in Mo targets, we aim to establish quantitative correlations between target microstructure, sputtering dynamics, and the performance of deposited thin films. This approach enables the optimization of Mo thin films for specific TFT applications, potentially enhancing device performance and manufacturing efficiency in display technologies

In pressure vessel design, understanding material toughness is critical. This challenge becomes more pronounced when designing vessels using strain rate sensitive materials, due to their low toughness determined from high strain rate tests, such as impact tests. This paper is focused on the design of a pressure vessel made from nominally pure molybdenum, with toughness properties sensitive to the strain rate, due (in part) to its bodycentred cubic (BCC) structure. The material is manufactured from a powder subjected to hot isostatic pressing. The applied approach presented here not only describes some of the factors involved in characterizing materials for a pressure vessel design, but also presents a general approach that should be applicable to other strain rate sensitive materials. In this paper we consider the measurement of fracture toughness and other material properties at different temperatures, including the criteria for specimen design, and determining test parameters based on the intended application. We also consider the information necessary for pressure vessel lifetime assessment, based on a fracture mechanics approach.

The use of hot isostatically pressed isotropic pure molybdenum was recently processed through ASME Section VIII. This is a unique material for the manufacture of pressure vessels as pure molybdenum is typically used for applications such as refractory, resistance wire for heating elements and structural thermal barrier components for internal furnaces for hot isostatic presses. There are several specifications for coverage of molybdenum such as ASTM B387, Standard Specification for Molybdenum and Molybdenum Alloy Bar, Rod, and Wire [1], and ASTM B386/B386M, Standard Specification for Molybdenum and Molybdenum Alloy Plate, Sheet, Strip, Foil, and Ribbon [2]. This paper demonstrates the test data needed for ASME approval of this unique material. The paper highlights the gaps in ASME Section II, Part D Appendix 5 and attempts to illustrate the “other information required by the Construction Committee” which may be needed for new materials today. This includes not only the data required by ASME Section II Part D, Appendix 5 [3,4], but also includes additional data which is required for more modern design by analysis techniques, such as elastic-plastic local strain limits and generation of true stress – true strain curves. This paper will also discuss alternative design philosophy approaches which were adopted in lieu of traditional approaches in areas such as fatigue analysis, determination of minimum design metal temperature (MDMT), and alternative approaches to examination and inspection of the material.