Browsing by Subject "aluminum alloys"

Now showing 1 - 5 of 5

Bond Characterization in Very High Power Ultrasonic Additive Manufacturing
(University of Texas at Austin, 2010-09-23) Sriraman, M.R.; Hiromichi, Fujii; Gonser, Matt; Babu, S.S.; Short, Matt
Solid parts were produced by Very High Power Ultrasonic Additive Manufacturing (VHP-UAM) at room temperature using 150 μm thick tapes of 6061 aluminum and 110 copper alloys. Processing was done at 20 kHz frequency over a range of parameters (26 –36 μm vibration amplitude, 5.6 – 6.7 kN normal force, and 30.5 - 35.5 mm/s travel speed). Softening of materials (up to about 14% in 6061 Al and 23% in 110 Cu) was noted facilitating enhanced plastic flow and a reduction in interfacial voids. Evolution of fine recrystallized grains (0.3-4 μm in 6061 Al and 0.3-10 μm in 110 Cu) from an initial coarser grain structure (up to 8 μm in 6061 Al and 25 μm in Cu) was observed at the build interface regions. Bonding between layers in both materials seems to have occurred by dynamic recrystallization and movement of grain boundaries across the interface. The energy required for the above physical processes is derived from interfacial adiabatic plastic deformation heating.
Comparison of AlSi10Mg and Al 6061 Processed through DMLS
(University of Texas at Austin, 2014) Fulcher, Benjamin A.; Leigh, David K.; Watt, Trevor J.
Direct Metal Laser Sintering (DMLS) processing of aluminum alloys has been primarily limited to a casting grade of aluminum, AlSi10Mg. The reasons for the choice of AlSi10Mg by machine manufacturers are presently unknown; however, it is suspected that the reduced coefficient of thermal expansion (CTE) due to the presence of Silicon may enhance DMLS processability. Aluminum 6061 (Al 6061) is a commonly used alloy across a wide range of industries and applications, and Harvest has observed a high interest in DMLS-manufactured Al 6061 products. However, the higher CTE value potentially presents greater challenges in controlling the shrinkage-induced warp common during DMLS. The work presented in this paper was performed in an effort to understand differences in manufacturability as well as mechanical properties of DMLS-processed AlSi10Mg and Al 6061.
Effect of Process Gas and Powder Quality on Aluminum Alloys Processed by Laser Based Powder Bed Melting Process
(University of Texas at Austin, 2016) Bauer, D.M.; Dietrich, K.; Walter, M.; Forêt, P.; Palm, F.; Witt, G.
The production of parts and components by Additive Layer Manufacturing (ALM) offers potential cost benefits for aeronautic applications. Laser Based Powder Bed Melting Process offers design flexibility while enabling weight reduction due to topological optimization by substitute conventional design and manufacturing routes. Especially aluminum alloys are highly sensitive to oxygen and hydrogen impurity during the process. Due to this, it is mandatory to control precisely and hold a low oxygen level while processing. Hereby it is possible to avoid any negative impact on the final mechanical properties as tensile strength and fatigue resistance. For the investigations, aluminum powder (Al-Si-Mg) is used. This paper will present the influence of the oxygen level during processing on the final mechanical properties of the part. Even if pure Argon is commonly used to inert the chamber, different sources of oxygen like powder, equipment and gas supply have a negative impact and will be investigated. [1]–[4]
Mechanical Properties of Selective Laser Melted AlSi10Mg: Nano, Micro, and Macro Properties
(University of Texas at Austin, 2015) Aboulkhair, Nesma T.; Stephens, Alex; Maskery, Ian; Tuck, Chris; Ashcroft, Ian; Everitt, Nicola M.
The selective laser melting (SLM) of aluminium alloys is of great current interest at both the industrial and research levels. Aluminium poses a challenge to SLM compared with other candidate materials, such as titanium alloys, stainless steels, and nickel-based alloys, because of its high thermal diffusivity and low infrared absorptivity and tendency to result in relatively porous parts. However, recent studies have reported the successful production of dense AlSi10Mg parts using SLM. In this study, we report on the nano, micro, and macroscopic mechanical properties of dense AlSi10Mg samples fabricated by SLM. Nanoindentation revealed the hardness profile across individual melt pools building up the parts to be uniform. This is due to the fine microstructure and uniform chemical elements distribution developed during the process due to rapid solidification. Micro-hardness testing showed anisotropy in properties according to the build orientation driven by the texture produced during solidification. Lastly, the tensile and compressive behaviours of the parts were examined showing high strength under both loading conditions as well as adequate amounts of strain. These superior mechanical properties compared to those achieved via conventional manufacturing promote SLM as promising for several applications.
Selective Laser Melting of Al6061 Alloy: Processing, Microstructure, and Mechanical Properties
(University of Texas at Austin, 2018) Zhang, Jinliang; Song, Bo; Zhang, Lei; Liu, Jie; Shi, Yusheng
Selective laser melting (SLM) is considered as one of the most promising additive manufacturing (AM) technologies. Aluminum alloy is of wide application potentiality due to their high specific strength and heat resistance. In this study, Al6061 alloy was prepared via selective laser melting (SLM) and densification, microstructure and properties were investigated systematically. It was found that process parameters including laser power and scanning rate have a great effect on the forming quality and the porosity of the samples. The α-Al phase is observed in XRD results and (200) is the preferable orientations of α-Al crystal in the SLM process. The microstructure can be divided into three areas: fine grained area, coarse grained area and heat affected area. As for the nanohardness, with the increase of laser power, the elastic modulus and hardness of SLM aluminum alloy show the trend of increasing first and then decreasing, and with the increase of scanning speed, the hardness of SLMed aluminum alloy is gradually reduced. With the increasing laser power and decreasing scanning rate, the elastic modulus and hardness of the samples increased first and then decreased.