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Microstructural Characteristics of Laser Metal Deposited Magnesium Alloy AZ31
摘要： Up to now, only a limited amount of metallic materials is investigated for laser additive manufacturing (LAM). However, the demand to widen the application possibilities by enlarging the range of materials for LAM is growing fast. By now, titanium and aluminium alloys are in the focus of research. In contrast, magnesium alloys are rarely used in the field of additive manufacturing, although they possess a low density in combination with a high specific strength. Currently, magnesium structures are mainly produced by casting but during the last years, the use of wrought alloys also increased. A reason for the rare use of magnesium alloys for LAM technologies might be the high flammability of magnesium powders. This difficulty can be avoided by using magnesium wire for laser metal deposition (LMD). In the present study, the microstructural characteristics of a LMD processed AZ31 magnesium alloy are investigated. For this purpose, optical microscopy and scanning electron microscopy were used. With the help of EDX and EBSD analysis, a change of the chemical composition and micro texture with structure height was identified. The relationship of microstructure and local mechanical properties was investigated with the help of Vickers micro hardness testing. Based on the obtained results it can be concluded that the microstructural characteristics of laser additive manufactured magnesium alloys differ from those of titanium and aluminium alloys. Thus, a wider application spectrum of LMD and magnesium alloys can be opened up.
关键词： laser metal deposition,local mechanical properties,microstructure,magnesium alloy,wire,microtexture
更新于2025-11-28 14:24:20
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Facile fabrication of multi-scale microgroove textures on Ti-based surface by coupling the re-solidification bulges derived from nanosecond laser irradiation
摘要： A facile method is proposed to fabricate multi-scale microgroove textures (MGT) on Ti-based implant material. The effect of some primary parameters on the morphology of laser-irradiated surface is studied in detail. The results show that at the scanning speed of 42 mm/s, when the laser intensity is ≥4.0 J/cm2 typical microgroove structure with raised edges is produced by single-line scanning irradiation, and various MGT can be easily fabricated by multi-line scanning irradiation through properly adjusting the scanning interval in accordance with the feature size of microgroove structures. Meanwhile, it is firstly found that multi-scale MGT perpendicular to the scanning direction can be achieved by applying suitable high scanning speed with small scanning interval. Using a laser spot with the diameter of 20 μm, multi-scale MGT with various periods ranging from 15 (less than the laser spot diameter) to 35 μm are successfully fabricated on TA2 surfaces, and perpendicular ones with the same period of 21 μm but different ridge widths are also obtained. The aspect ratio of these MGT is > 1.5. Wettability measurements reveal that the water droplet on the produced multi-scale MGT owns anisotropic spreading speeds or spreading lengths. The energy dispersive spectroscopy tests indicate that their ridges are rich in titanium oxides which are good hemo-compatibility materials. The proposed method has a promising application for fabricating multi-scale MGT like those on natural vessel to the stent surface to improve its hemo-compatibility.
关键词： Microtexture,Functional surface,Anisotropic wettability,Laser irradiation,Microgroove
更新于2025-09-23 15:19:57