TY - CONF A1 - Engelking, Lorenz T1 - Alloy modification for additive manufactured Ni alloy components Part II: Effect on subsequent machining properties N2 - Alloy 36 (1.3912), also known as “Invar”, is an alloy with 36% nickel. It was developed in 1897 by Guillaume and stands out for its very low thermal expansion coefficient. It is classified as a difficult-to-cut material and is commonly used for the production of fiber-reinforced composites in the field of mold construction. Additive manufacturing (AM) offers many economic advantages regarding the repair, modification and manufacture of entire components. Subsequent machining of the AM components is necessary to account for complex structures, final contours or defined surfaces. In part I of this investigation, the initial alloy 36 is modified with the elements Ti, Zr and Hf up to a maximum of 0.33 wt.-%. The influence of the modification elements on the microstructure as well as on the hardness of the AM components is examined. Part II focusses on the effect of the alloy modifications on machinability as well as on the surface integrity of plasma-transferred-arc-welded (PTA) and finish milled invar components. Machining tests were carried out, to investigate the influence of ultrasonic assistance and the effects of modification elements Ti, Zr and Hf on the occurring cutting forces, temperatures and resulting surface integrity of the AM components made of alloy 36 and their modifications. The results show a significant positive influence of ultrasonic assistance on the resulting cutting force as well as on the roughness of all materials investigated. T2 - 75th IIW Annual Assembly CY - Tokyo, Japan DA - 17.07.2022 KW - Alloy modification KW - Alloy 36 KW - Additive manufacturing KW - Ultrasonic-assisted milling KW - Surface integrity PY - 2022 AN - OPUS4-55432 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Engelking, Lorenz T1 - Effect of alloy modification for additive manufactured Ni alloy components on microstructure and subsequent machining properties N2 - Ni alloys are generally classified as difficult-to-cut materials and cost intensive. Additive manufacturing (AM) offers economic advantages. However, machining of these AM components is mandatory to create the final contour or surface. The inhomogeneous and anisotropic microstructure and properties of AM components causes an unstable cutting process. Moreover, undesirable tensile residual stresses are generated due to subsequent machining. In this investigation, the initial alloy 36 is modified with Ti and Nb up to 1.6 wt.-% and build-up welded via gas metal arc welding (GMAW) and plasma-transferred-arc (PTA). Then, finish-milling tests are carried out to investigate the influence of the modification as well as the cutting parameters on the resulting cutting force and the surface integrity. In addition, the conventional milling process (CM) is compared with the ultrasonic-assisted milling process (US), which has a significant influence on the machinability as well as on the surface integrity. T2 - Additive Fertigung – Werkstoffe – Prozesse – Wärmebehandlung 2022 CY - Bremen, Germany DA - 29.06.2022 KW - Additive manufacturing KW - Alloy 36 KW - Alloy modification KW - Ultrasonic-assisted milling KW - Surface integrity PY - 2022 AN - OPUS4-55429 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Treutler, K. T1 - Nickel-iron-alloy modification to enhance additively welded microstructure for subsequent milling N2 - The aerospace industry uses nickel-iron-alloys to create moulding tools for composite materials because of the low coefficient of thermal expansion. These tools have a large-sized and complex structure, making them cost-intensive and difficult to manufacture. Therefore, the focus is set on additive manufacturing, which can additionally enable the repair of components in order to eliminate local defects. However, the process usually results in a heterogeneous microstructure and anisotropic mechanical properties. As there is a high demand for a precise and exact fit of the precision moulds and thus the surface quality, the welded components must be subsequently machined. Nickel-iron alloys are difficult to machine and an inhomogeneous microstructure also leads to unstable cutting forces. Consequently, a refinement and homogenisation of the microstructure morphology is achieved through specific alloy modifications in order to stabilise and improve the subsequent machining process. Studies on the refinement of FeNi 36 based on vacuum arc melting furnaces are used as a starting point. Therefore, titanium and niobium are chosen as modification elements with a maximum 1 % weight percent and are added to nickel-iron base alloy. The elements are alloyed and build-up welded by using plasma-transferred-arc welding. The resulting microstructure morphology of the welded wall structure and the machining properties are then determined. Furthermore, the influence on the coefficient of thermal expansion is investigated in connection with the modification and the welding process itself. It can be shown that even small amounts of niobium have a significant influence on the structural morphology of the welded layers during plasma-transferred-arc welding. T2 - 2nd international Conference on Advanced Joining Processes 2021 CY - Sintra, Portugal DA - 21.10.2021 KW - Alloy modification KW - Ultrasonic-assisted milling KW - Nickel-iron-alloy KW - Additive manufacturing KW - Plasma transferred arc welding PY - 2021 AN - OPUS4-53635 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rhode, Michael T1 - Joining processes for components in hydrogen technologies: Current need and future importance N2 - This presentation gives an overview on the importance of joining processes for component fabrication in hydrogen technologies. For that reason, the current need and future research and developement activites are highlighted for the three technological fields: hydrogen storage, transport and use (in terms of the emerging field of additive manufacturing). Finally, some remarks are given for necessary changes in the standardization. T2 - IIW Intermediate Meeting, Comm. II-A "Welding Metallurgy" CY - Online meeting DA - 17.03.2022 KW - Hydrogen KW - Welding KW - Research KW - Review KW - Additive manufacturing PY - 2022 AN - OPUS4-54488 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Engelking, Lorenz T1 - Optimisation of surface residual stresses using hybrid milling processes for additive manufactured Ni alloy components N2 - Ni alloys are cost intensive materials and generally classified as difficult-to-cut materials. However, machining of these materials is needed especially in case of alloy 36 (1.3912), which is commonly used in mould construction for the production of fibre-reinforced composites. With regard to repair, modification and manufacturing of such components, additive manufacturing offers significant economic advantages. Nevertheless, subsequent machining steps are needed to achieve the final component contour and defined surface conditions. Dependent on the material and machining process conditions, detrimental tensile residual stresses may be the result on the machined surface, having negative impact on the component performance and safety. Recent studies exhibited that hybrid machining processes, such as ultrasonic-assisted milling (USAM), are suitable for achieving favourable residual stress states at the surface of difficult-to-cut Ni-Cr alloys. In this investigation, wire arc additive manufactured (WAAM) specimens of alloy 36 were finish milled under different milling conditions. In addition to the machined surfaces condition and topology, the surface-near residual stresses were analysed using X-ray diffraction (XRD). Especially for low cutting speeds, significantly improved surface properties, roughness parameters and lower mechanical and microstructural degradations were found for the specimen machined with USAM compared to conventional milling. The improved surface integrity could furthermore be observed by a significant reduction of the tensile residual stresses in the surface boundary area. T2 - ICRS11, 11th International Conference on Residual Stresses CY - Nancy, France DA - 27.03.2022 KW - Surface integrity KW - Ultrasonic-assisted milling KW - Additive manufacturing KW - Ni alloy KW - Alloy 36 PY - 2022 AN - OPUS4-54904 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Barik, Birendra Kumar A1 - Chaurasia, Prashant Kumar A1 - De, Amitava T1 - Rapid estimation of temperature field and bead profile for wire arc directed energy deposition using an analytical heat conduction model N2 - A prior estimation of the temperature field and bead profile can help fabricate dimensionally consistent and structurally sound parts using wire arc directed energy deposition (DED-Arc). We present here a three-dimensional analytical heat transfer model with a volumetric heat source to compute the transient temperature field and melt pool dimensions for DED-Arc. The analytical model considers the thermal conductivity and volumetric heat capacity as a linear function of temperature. In contrast to assuming a pre-defined deposited track profile, the same is scaled from the analytically computed melt pool dimensions into the substrate. The computed deposit profiles of single and multiple tracks and layers are validated extensively with the corresponding experimentally measured results for a range of DED-Arc process conditions. KW - Additive manufacturing KW - Analytical model KW - Heat conduction analysis KW - Volumetric heat source KW - Deposit profile PY - 2025 DO - https://doi.org/10.1177/13621718251398070 SN - 1362-1718 SP - 1 EP - 14 PB - SAGE Publications AN - OPUS4-64836 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zurcher, Theo A1 - Serrano-Munoz, Itziar A1 - Mishurova, Tatiana A1 - Abreu Faria, Guilherme A1 - Degener, Sebastian A1 - Fridrici, Vincent A1 - Charkaluk, Eric A1 - Bruno, Giovanni T1 - Sliding wear resistance and residual stresses of parts repaired by laser metal deposition N2 - Large temperature gradients inherent to additive manufacturing (AM) processes induce large residual stress (RS) in the final part. Because RS can influence the tribological properties, this study focuses on the relationship between wear sliding properties and RS in IN718 coatings. Such coatings were deposited with a Laser metal deposition (LMD) machine using two different scanning strategies. The wear resistance and RS state were investigated after surface milling. RS were measured before and after wear tests on a reciprocating sliding test apparatus. Two different X-ray diffraction techniques were employed to measure the surface and subsurface state RS: Laboratory Energy Dispersive X-ray Diffraction (LEDXD) and Synchrotron X-ray Energy Dispersive Diffraction (SXEDD). Due to the milling process, the coatings show similar depth distributions of RS from 22 to 92 μm depth, but exhibit different magnitudes depending on the scanning strategy used. Reciprocating sliding wear tests induced high compressive residual stresses that erased the initial RS state, and a similar wear behavior was observed in the two samples. These samples possess similar texture and grain morphology. This demonstrates that the influence of RS on wear resistance is a second-order effect. Nevertheless, it was observed that RS can still impact the wear performance at the early testing stages of the repaired parts. KW - Additive manufacturing KW - Wear resistance KW - Residual stress PY - 2023 DO - https://doi.org/10.1007/s10853-023-09129-4 SN - 0022-2461 SP - 1 EP - 18 PB - Springer AN - OPUS4-59084 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schröpfer, Dirk T1 - Influence of Ultrasonic-Assisted Milling on Surface Integrity of Additively Manufactured Components Using DED-Arc/GMAW N2 - Additive manufacturing (AM) is increasingly used for producing complex metallic com-ponents. Subsequent machining is essential to achieve final geometries and surface conditions. The resulting surface integrity, particularly the near-surface residual stress state, plays a crucial role in component performance and fatigue life. This study inves-tigates the potential of ultrasonic-assisted milling (USAM), a hybrid machining process, to improve surface integrity and machinability compared to conventional milling (CM). Three materials were investigated, two difficult-to-cut materials CoCr26Ni9Mo5W and FeNi36 and a low-alloy steel S355J2C. The CoCr26Ni9Mo5W and FeNi36 were addi-tively manufactured via DED-Arc and then machined with varying cutting speeds and feed rates within a Design of Experiments. USAM exhibited enhanced machinability and surface integrity, particularly at low cutting speeds, by reducing cutting forces up to 40% and shifting near-surface residual stresses from tensile to compressive. For S355J2C, USAM reduced cutting forces by approximately 45% and induced surface-near compressive residual stresses up to approximately -700 MPa, leading to a 11% higher fatigue strength compared to CM. These findings highlight the advantages of ultrasonic assistance in post-AM machining, offering enhanced fatigue performance and surface quality for various metallic materials. T2 - 4th International Conference on Advanced Joining Processes 2025 CY - Coimbra, Portugal DA - 16.10.2025 KW - Ultrasonic-assisted milling KW - Additive manufacturing KW - Surface integrity KW - Fatigue strength KW - Residual stress PY - 2025 AN - OPUS4-65051 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ávila Calderón, Luis T1 - Mechanical behaviour of AM metals: Creep of LPBF 316L and low-cycle-fatigue of LMD Ti-6Al-4V N2 - Additively manufactured metallic materials have already started to find application in safety-relevant components. However, this has only happened for certain materials and specific applications and loading conditions, since there is still an extensive lack of knowledge as well as of historical data regarding their mechanical behaviour. This contribution aims to address this lack of understanding and historical data concerning the creep behaviour of the austenitic stainless steel 316L manufactured by Laser-Powder-Bed-Fusion (L-PBF) and the low-cycle-fatigue behaviour of the titanium alloy Ti-6Al-4V manufactured by Laser-Metal-Deposition (LMD). Furthermore, it aims to assess their mechanical behaviour against their conventional counterparts. With that in mind, specimens from conventional and additive materials are tested and their mechanical behaviour analysed based on characteristic curves. To understand the damage behaviours the materials are characterized by destructive and non-destructive techniques before and after failure. T2 - 1st Workshop on In-situ Monitoring and Microstructure Development in Additive Manufacturing CY - Online Meeting DA - 10.12.2020 KW - Ti-6Al-4V KW - 316L KW - Additive manufacturing KW - Creep behaviour KW - Low-cycle-fatigue behaviour PY - 2020 AN - OPUS4-51879 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dzugan, J. A1 - Lucon, E. A1 - Koukolikova, M. A1 - Li, Y. A1 - Rzepa, S. A1 - Yasin, M.S. A1 - Shao, S. A1 - Shamsaei, N. A1 - Seifi, M. A1 - Lodeiro, M. A1 - Lefebvre, F. A1 - Mayer, U. A1 - Olbricht, Jürgen A1 - Houska, M. A1 - Mentl, V. A1 - You, Z. T1 - ASTM interlaboratory study on tensile testing of AM deposited and wrought steel using miniature specimens N2 - An interlaboratory study, involving eigth international laboratories and coordinated by COMTES FHT (Czech Republic), was conducted to validate tensile measurements obtained using miniature specimens on additively manufactured (AM) components and artifacts. In addition to AM 316L stainless steel (316L SS), a wrought highstrength steel (34CrNiMo6V, equivalent to AISI 4340) was also used. Based on the results, a precision statement in accordance with ASTM E691 standard practice was developed, intended for inclusion in a proposed annex to the ASTM E8/E8M tension testing method. The primary outcomes of the study highlighted the agreement between yield and tensile strength measured from miniature and standard-sized tensile specimens. Furthermore, most tensile properties exhibited similar standard deviations, offering users insight into the efficacy of miniature specimen applications. KW - 316L stainless steel KW - Additive manufacturing KW - High-strength steel KW - Miniature specimens KW - Tensile tests PY - 2024 DO - https://doi.org/10.1016/j.tafmec.2024.104410 SN - 0167-8442 VL - 131 SP - 1 EP - 13 PB - Elsevier B.V. AN - OPUS4-60180 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -