TY - JOUR A1 - Delgado Arroyo, Diego A1 - Richter, Tim A1 - Schroepfer, Dirk A1 - Boerner, Andreas A1 - Rhode, Michael A1 - Lindner, T. A1 - Preuß, B. A1 - Lampke, T. T1 - Influence of Milling Conditions on AlxCoCrFeNiMoy Multi-Principal-Element Alloys JF - Coatings N2 - Multi-Principal-Element or High-Entropy Alloys (MPEAs/HEAs) have gained increasing interest in the past two decades largely due to their outstanding properties such as superior mechanical strength and corrosion resistance. However, research studies on their processability are still scarce. This work assesses the effect of different machining conditions on the machinability of these novel alloys, with the objective of advancing the introduction of MPEA systems into industrial applications. The present study focuses on the experimental analysis of finish-milling conditions and their effects on the milling process and resulting surface finish of CoCrFeNi, Al0.3CoCrFeNi and Al0.3CoCrFeNiMo0.2 alloys fabricated via Spark Plasma Sintering. Ball-nose-end milling experiments have been carried out various milling parameters such as cutting speed, feed per cutting edge, and ultrasonic assistance. In situ measurements of cutting forces and temperature on the tool edge were performed during the experiments, and surface finish and tool wear were analyzed afterwards. The results exhibited decreasing cutting forces by means of low feed per cutting edge and reduced process temperatures at low cutting speed, with the use of ultrasonic-assisted milling. It was shown that the machinability of these modern alloys through conventional, as well as modern machining methods such as ultrasonic-assisted milling, is viable, and common theories in machining can be transferred to these novel MPEAs. KW - Multi-principal element alloys KW - Finish milling KW - Spark plasma sintering KW - Ultrasonic-assisted milling KW - Microstructure characterization PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572990 DO - https://doi.org/10.3390/coatings13030662 VL - 13 IS - 3 SP - 1 EP - 18 PB - MDPI (Multidisciplinary Digital Publishing Institute) CY - Basel (CH) AN - OPUS4-57299 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rhode, Michael A1 - Erxleben, Kjell A1 - Richter, Tim A1 - Schroepfer, Dirk A1 - Michael, Thomas T1 - Dissimilar metal TIG weld joints of multiple principal element alloys (MPEA) to austenitic steel 304 N2 - Multi-element alloys (MPEA - Multiple Principal Element Alloys) represent a new class of materials consisting of at least three alloying elements, each with 5 to 35 atomic %. This material class includes high-entropy alloys (HEA, with n ≥ 4 elements). The underlying alloying concept differs fundamentally from conventional materials such as the Fe-based steel. For this purpose, the alloying elements are specifically selected, and the microstructures are adjusted in a single-phase and, in some cases, multi-phase manner. The aim is to identify highly innovative MPEA with individually adjustable properties for industrial applications. In the last 20 years, however, the focus has been on pure material synthesis. With the increase in available material quantities, the focus is on processing issues such as joining and welding processes. In that connection, the weldability of MPEAs has received very little attention so far. Experience with dissimilar metal welds (DMWs) is completely lacking but is essential for the application of these materials if joint to conventional materials. This study presents selected experimental results on the weldability of MPEA-DMWs and the resulting microstructures. For this purpose, the equiatomic CoCrFeMnNi (HEA) was investigated in cold-rolled (CR) and heat-treated (HT) condition and joined by tungsten inert gas (TIG) welding to an austenitic stainless steel 304. The DMWs showed defect-free conditions (no lack of fusion, cracks and so on), whereas the cold-rolling increases the microhardness. The global mechanical properties were obtained by instrumented tensile tests of cross-weld samples and showed sufficient yield and tensile strength comparable to that of the individual base materials (BM). The local strain conditions were determined by digital image correlation and showed the highest local strains to occur in the intermixed weld metal. Indeed, the preferred fracture location of the cross-weld tensile samples was in the weld metal. Finally, the experiments proofed the weldability of the MPEAs to conventional 304. This enables targeted further considerations for example as structural materials. T2 - FEMS EUROMAT 2023 CY - Frankfurt a. M., Germany DA - 04.09.2023 KW - Multi-principal element alloys KW - TIG welding KW - Dissimilar metal weld (DMW) joint KW - Microstructure KW - Mechanical properties KW - Digital Image Correlation (DIC) PY - 2023 AN - OPUS4-58222 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -