@misc{GruegerJenschDittrichetal., author = {Gr{\"u}ger, Lennart and Jensch, Felix and Dittrich, Fabian and H{\"a}rtel, Sebastian}, title = {On the creation of a material bond between L-PBF-manufactured AZ91 and Ti-6Al-4V components in the context of medical applications}, series = {Materials}, volume = {17}, journal = {Materials}, number = {18}, publisher = {MDPI AG}, issn = {1996-1944}, doi = {10.3390/ma17184667}, abstract = {Within the scope of these investigations, the feasibility of a material bond between Ti-6Al-4V and the magnesium alloy AZ91 is analyzed. Ti-6Al-4V is frequently used for implants due to its biocompatibility, corrosion resistance, and specific strength. However, depending on the surface quality, the attachment behavior of the bone to the implant varies. Magnesium implants promote the regeneration of bone tissue and biodegrade as the bone tissue heals. Combining the properties of both materials in one implant enables a reduced implant volume and increased stability. For this reason, this study aims to demonstrate the feasibility of creating a material bond between the materials Ti-6Al-4V and AZ91. For this purpose, Ti-6Al-4V truncated cones and AZ91 sleeves were produced using the additive manufacturing process of laser powder bed fusion (L-PBF). The as-built sleeves were then pressed onto machined truncated cones. Since zinc serves as a lubricant and has good diffusion properties with the materials used as a result of heat treatment, a comparison was made between zinc-coated and the as-built Ti-6Al-4V samples. This showed that a bond was created after hot isostatic pressing and that the push-out force could be increased by more than 4.5 times. Consequently, a proof of feasibility was demonstrated, and a high potential for applications in medical technology was shown.}, language = {en} } @misc{KaarsDittrichMayretal., author = {Kaars, Jonny and Dittrich, Fabian and Mayr, Peter and Hensel, Jonas}, title = {Welding of 42SiCr treated by quenching and partitioning : mechanical properties of the HAZ and preheating proposal}, series = {Welding in the world : the international journal of materials joining}, journal = {Welding in the world : the international journal of materials joining}, publisher = {Springer}, address = {Berlin}, doi = {10.1007/s40194-025-02032-3}, pages = {1 -- 13}, abstract = {A 42SiCr experimental steel was heat-treated by the quenching and partitioning (Q\&P) heat treatment to achieve a combination of high strength and ductility. The associated microstructure is characterized in literature by finely distributed martensite laths with a small volume fraction of retained austenite embedded. The goal of this work is to provide a comprehensive characterization of the mechanical properties of all subzones in the heat-affected zone (HAZ) of welded 42SiCr-Q\&P steel. Dedicated microspecimens were subjected to a specifically selected thermal cycle in a dilatometer and characterized by mechanical testing and microstructural assessment. One specimen series is dedicated to the assessment of the mechanical properties of the material after welding; another four specimen series represent some carefully selected strategies to mitigate adverse effects of welding. Tensile testing revealed a decrease in yield strength in the HAZ by up to 35\%. The ductility of the material showed inverse behavior. Material in the supercritical zone shows > 2000 MPa of ultimate strength, but at the same time is very brittle. The most remarkable result showed that the embrittlement in the supercritical zone can be successfully mitigated by holding the material at temperatures in the range of 200-250 °C for 5 min upon cooling, resulting in a yield strength of around 1400 MPa along with a ductility of > 10\%, restoring the desired property combination. This very promising observation suggests fusion welding of 42SiCr-Q\&P might be possible by means of preheating, maintaining the superior mechanical properties of Q\&P in the weld.}, language = {en} }