Microstructure and Hardness of AlMg3 Alloy Subjected to Ultrasonic Upsetting

This study was conducted to study the effect ultrasonic vibrations on the evolution of the microstructure and hardness of the AlMg3 aluminum alloy in a solution treated condition. To understand the process physics in this article, after the deformation the microstructures of the samples before and after deformation were analyzed by the light and electron microscopy, including the electron backscatter diffraction (EBSD) analysis. The result evidently shows that the ultrasonic-assisted deformation has a meaningful influence on the grain refinement – the application of the USV enhances the formation of deformation bands and new sub-grains. This resulted in a certain hardness enhancement.

Strength Enhancement Study on Composites of AA6066 Aluminium Alloy with Magnesium Oxide and Coal Ash

Aluminium alloy is the most favourable material based on the various properties and economic factors. Always there are so many researches going on based on the enhancement of the material properties with various combinations and the various materials mixing rate depending upon the availability. These researches were focused on the augmentations of the properties, and then the corresponding properties can be used in the various applications depending upon the results. In this study, the AA6066 aluminium alloy composites were created with the magnesium oxide and coal ash with a variety of grouping. The specimens were named as AAMgOCA 1 to AAMgOCA 6 with respect to the volume concentration composition. Then, the composites were tested to identify the impact on various strengths such as yield strength, ultimate tensile strength, shear strength, and flexural strength. These strengths were compared with the two conditions of the composites such as annealed and heat-treated conditions. AAMgOCA 3 has the greatest results in heat-treated condition when compared with the annealed condition.

Epistaxis

Epistaxis, also known as nosebleeds, is a commonly treated condition in medicine and especially otolaryngology. 1 in 200 emergency room visits are due to acute epistaxis, with a higher frequency during the winter and among young children and the elderly. A strong understanding of the etiology, anatomy, and available therapeutic options is necessary for optimal management of epistaxis.1,2 This review contains 11 figures, 5 tables, 1 video, and 66 references. Keywords: epistaxis, nose bleed, nasal packing, hemostasis, nasal cauterization, arterial ligation, arterial embolization, hereditary hemorrhagic telangiectasias

CARTECH Ti 15V-3Cr-3Sn-3Al

CarTech Ti 15V-3Cr-3Sn-3Al (UNS R58153) is a metastable beta titanium alloy that offers substantial weight reduction in comparison with other engineering materials. If used in the solution heat treated condition, the alloy has excellent cold formability. In the aged condition, the alloy has high strength. It is acceptable for use up to 230 °C (550 °F). This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, and joining. Filing Code: Ti-180. Producer or source: Carpenter Technology Corporation.

UDDEHOLM UHB 11

Uddeholm UHB 11 is a medium-carbon, non-alloy cold-work tool steel. It is primarily used in the non-heat-treated condition. For special applications it is used in the quenched and tempered condition. Owing to its low hardenability, Uddeholm UHB 11 develops a fully hardened zone that is relatively thin, even when quenched drastically. Thicker sections have a hard case over a tough core. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on forming, heat treating, and joining. Filing Code: TS-814. Producer or source: Uddeholms AB.

Fatigue Improvement of AlSi10Mg Fabricated by Laser-Based Powder Bed Fusion through Heat Treatment

This study aimed to identify an optimal heat-treatment parameter set for an additively manufactured AlSi10Mg alloy in terms of increasing the hardness and eliminating the anisotropic microstructural characteristics of the alloy in as-built condition. Furthermore, the influence of these optimized parameters on the fatigue properties of the alloy was investigated. In this respect, microstructural characteristics of an AlSi10Mg alloy manufactured by laser-based powder bed fusion in non-heat-treated and heat-treated conditions were investigated. Their static and dynamic mechanical properties were evaluated, and fatigue behavior was explained by a detailed examination of fracture surfaces. The majority of the microstructure in the non-heat-treated condition was composed of columnar grains oriented parallel to the build direction. Further analysis revealed a high fraction of pro-eutectic α-Al. Through heat treatment, the alloy was successfully brought to its peak-hardened condition, while eliminating the anisotropic microstructural features. Yield strength and ductility increased simultaneously after heat treatment, which is due to the relief of residual stresses, preservation of refined grains, and introduction of precipitation strengthening. The fatigue strength, calculated at 107 cycles, improved as well after heat treatment, and finally, detailed fractography revealed that a more ductile fracture mechanism occurred in the heat-treated condition compared to the non-heat-treated condition.

Fatigue Improvement of AlSi10Mg Fabricated by Laser-Based Powder Bed Fusion through Heat-Treatment.

This study aims to identify an optimal heat-treatment parameter set for an additively manufactured AlSi10Mg alloy in terms of increasing the hardness and eliminating the anisotropic microstructural characteristics of the alloy in as-built condition. Furthermore, the influence of these optimized parameters on the fatigue properties of the alloy investigated. In this respect, microstructural characteristics of an AlSi10Mg alloy manufactured by Laser-Based Powder Bed Fusion in non-heat-treated and heat-treated conditions were investigated. Their static and dynamic mechanical properties were evaluated, and fatigue behavior was explained by a detailed examination of fracture surfaces. Much of the microstructure in the non-heat-treated condition was composed of columnar grains oriented parallel to the build direction. Further analysis revealed a high fraction of pro-eutectic α-Al. Through heat-treatment, the alloy was successfully brought to its peak-hardened condition, while eliminating the anisotropic microstructural features. Yield strength and ductility increased simultaneously after heat-treatment, which is due to the relief of residual stresses, preservation of refined grains, and introduction of precipitation strengthening. The fatigue strength, calculated at 10^7 cycles, improved as well after heat-treatment and finally detailed fractography reviled that a more ductile fracture mechanism has happened in the heat-treated condition compared to the non-heat-treated condition.

Effect of Thermomechanical Treatments on the Mechanical Properties of New Low-Cost Ti-Fe-Nb-Zr Alloys

The development of new low-cost alloys composed of common elements that show high biocompatibility and mechanical properties matching with human bone is the target of many researches recently. Design and controlling the mechanical properties of newly developed set of Ti-xFe-3Zr-yNb (x=3-8 & y=2-3, at.%) low-cost alloys through applying different thermomechanical treatments is the aim of this work. Fe-content in the present designed alloys is changing in the range 3 to 8 at.%. The hardness and Young's modulus of the alloys were measured for the alloys in the solution treated, hot rolled and subsequent ageing at 400 °C and 550 °C. The phases separation and hence hardness of the aged alloys at 400 °C and 550 °C are highly dependent on the Fe-content in the alloy. The Young's modulus of the alloys is also changing with the Fe-content and heat treatment, where lowest modulus (~80GPa) is shown in the Ti-5Fe-3Zr-3Nb alloy in the solution treated condition.

Computational analysis of the effects of geometric irregularities and post-processing steps on the mechanical behavior of additively manufactured 316L stainless steel stents

Advances in additive manufacturing enable the production of tailored lattice structures and thus, in principle, coronary stents. This study investigates the effects of process-related irregularities, heat and surface treatment on the morphology, mechanical response, and expansion behavior of 316L stainless steel stents produced by laser powder bed fusion and provides a methodological approach for their numerical evaluation. A combined experimental and computational framework is used, based on both actual and computationally reconstructed laser powder bed fused stents. Process-related morphological deviations between the as-designed and actual laser powder bed fused stents were observed, resulting in a diameter increase by a factor of 2-2.6 for the stents without surface treatment and 1.3-2 for the electropolished stent compared to the as-designed stent. Thus, due to the increased geometrically induced stiffness, the laser powder bed fused stents in the as-built (7.11 ± 0.63 N) or the heat treated condition (5.87 ± 0.49 N) showed increased radial forces when compressed between two plates. After electropolishing, the heat treated stents exhibited radial forces (2.38 ± 0.23 N) comparable to conventional metallic stents. The laser powder bed fused stents were further affected by the size effect, resulting in a reduced yield strength by 41% in the as-built and by 59% in the heat treated condition compared to the bulk material obtained from tensile tests. The presented numerical approach was successful in predicting the macroscopic mechanical response of the stents under compression. During deformation, increased stiffness and local stress concentration were observed within the laser powder bed fused stents. Subsequent numerical expansion analysis of the derived stent models within a previously verified numerical model of stent expansion showed that electropolished and heat treated laser powder bed fused stents can exhibit comparable expansion behavior to conventional stents. The findings from this work motivate future experimental/numerical studies to quantify threshold values of critical geometric irregularities, which could be used to establish design guidelines for laser powder bed fused stents/lattice structures.