William H. Peter

Recyclability study on Inconel 718 and Ti-6Al-4V powders for use in electron beam melting

Powder bed-based additive manufacturing technologies offer a big advantage in terms of reusability of the powders over multiple cycles that result in cost savings. However, currently there are no standards to determine the factors that govern the powder reuse times. This work presents the results from a recyclability study conducted on Inconel 718 and Ti-6Al-4V powders. It has been found that the Inconel 718 powders are chemically stable over a large number of cycles and their reuse time is limited by physical characteristics of powders such as flowability. Ti-6Al-4V, on the other hand, finds its reuse time governed by the oxygen pick up that occurs during and in between build cycles. The detailed results have been presented.

Evaluation of Low Cost Titanium Alloy Products

Titanium has extremely attractive properties for air vehicles ranging from excellent corrosion resistance to good compatibility with graphite reinforced composites and very good damage tolerance characteristics. At current Buy to Fly ratios, the F-35 Program will consume as much as seven million pounds of titanium a year at rate production. This figure is nearly double that of the F-22 Program, which has a much higher titanium content. Lockheed Martin has initiated “Project Black Ti” to reduce the cost of titanium parts by reducing the titanium consumption but not the quantity of titanium parts. Ultimately, we want to reduce the inherent waste in the current processing of titanium alloy products. The Kroll process, by which most titanium product is made today, is nearly 60 years old. Kroll himself predicted the process would be replaced within 15 years due to inherent inefficiencies – in 1950. Titanium is also mis-characterized as a precious metal, which it is not. It is the ninth most abundant element on the earth’s surface. Aluminum by comparison is the third most abundant but has a much more efficient method to convert it to a usable form. Until the turn of the 20th century, aluminum was considered to be as precious as platinum until the Bayer Process brought prices down from

Consolidation Process in Near Net Shape Manufacturing of Armstrong CP-Ti/Ti-6Al-4V Powders

1200/kg to

Direct digital additive manufacturing technologies: Path towards hybrid integration

0.60/kg. Regarding titanium, one way to improve efficiency and buy less material to make the same parts is via Powder Metallurgy (PM). Until recently, titanium alloy powder was very expensive. However, new methods of producing titanium alloy have been developed which generate powder as an output versus massive ingots, which require multiple melts to achieve homogeneity. With powder, in theory, we should be able to get much closer to net shape and reduce the initial buy and reduce significant machining costs. These low cost titanium powders are becoming commercially available, which has the potential to initiate a paradigm shift in the applications of titanium. PM technologies and the consolidation of these new powders are now economically viable with the potential cost of the new powders running approximately an order of magnitude less than conventional PM grade powders. This paper will present the current status of “Project Black Ti” and its potential impact to the F-35 program.

Investigation of Pressing and Sintering Processes of CP-Ti Powder Made by Armstrong Process

This paper summarizes our recent efforts to develop the manufacturing technologies of consolidated net-shape components by using new low-cost commercially pure titanium (CP-Ti) and Ti-6Al-4V alloy powders made by the Armstrong process. Fabrication processes of net shape/ near net shape components, such as uniaxial die-pressing, cold isostatic pressing (CIP), sintering, roll compaction and stamping, have been evaluated. The press-and-sinter processing of the powders were systematically investigated in terms of theoretical density and microstructure as a function of time, pressure, and temperature. Up to 96.4% theoretical density has been achieved with the press-and-sinter technology. Tensile properties of the consolidated samples exhibit good ductility as well as equivalent yield/ultimate tensile strengths to those of fully consolidate materials, even with the presence of a certain amount of porosity. A consolidation model is also under development to interpret the powder deformation during processing. Net shape components made of the Armstrong powder can successfully be fabricated with clearer surface details by using press-and-sinter processing.

Current Status of Ti PM: Progress, Opportunities and Challenges

In the past decade, additive manufacturing and printed electronics technologies have expanded rapidly on a global scale. As the additive manufacturing techniques have become more capable and affordable, and able to work with a broader range of materials, the machines are increasingly being used to make advanced products at significantly lower costs and risks. The additive manufacturing industry is populated by a broad family of technologies, and the present paper provides an overview of key additive manufacturing technologies and their impact on materials processing, device applications, and future markets. Our R&D efforts on the development of core technologies for the realization of flexible electronics, and 3D microscale structures are also highlighted.

Corrosion Resistances of Iron-Based Amorphous Metals with Yttrium and Tungsten Additions in Hot Calcium Chloride Brine & Natural Seawater: Fe48Mo14Cr15Y2C15B6 and W-Containing Variants

This work used in-situ and ex-situ techniques to investigate the pressing and sintering processes of commercially pure (CP) Ti powder made by the Armstrong process. The objective is to simulate the actual manufacturing process of near net shape Ti components. Ti powders were uniaxially pre-pressed at designated pressures up to 100 ksi to form disk samples with different theoretical densities. Compression tests were performed in an SEM at different temperatures to obtain the mechanical properties and deformation behavior of these samples. Ex-situ technique was used to track the powder deformation process of disk samples from low pressure to high pressure. In-situ sintering was also performed in an SEM to record the morphology change of the porosities on the sample surface during the sintering process. The results will provide valuable information for optimizing the manufacturing process of high-density near net shape Ti components.

Shear Rolling of Magnesium Sheet for Automotive, Defense, and Energy Applications

Utilization of titanium components made by powder metallurgy methods has had limited acceptance largely due to the high cost of titanium (Ti) powder. There has been renewed interest in lower cost economical powders and several Ti reduction methods that produce a particulate product show promise. This talk summarizes work done at Oak Ridge National Laboratory to consolidate these economical powders into mill products. Press and sinter consolidation, hot isostatic pressing (HIP) and direct roll consolidation to make sheet have been explored. The characteristics of the consolidated products will be described as a function of the consolidation parameters.

Variability in Fatigue Behavior of a Zr-Based Bulk Metallic Glass (BMG) as a Result of Average Surface Roughness and Pronounced Surface Defects

Yttrium-containing SAM1651 (Fe{sub 48.0}Cr{sub 15.0}Mo{sub 14.0}B{sub 6.0}C{sub 15.0}Y{sub 2.0}), has a critical cooling rate (CCR) of approximately 80 Kelvin per second, while SAM2X5 (Fe{sub 49.7}Cr{sub 17.7}Mn{sub 1.9}Mo{sub 7.4}W{sub 1.6}B{sub 15.2}C{sub 3.8}Si{sub 2.4}) with no yttrium has a higher critical cooling rate of approximately 600 Kelvin per second. SAM1651s low CCR enables it to be rendered as a completely amorphous material in practical materials processes. Chromium (Cr), molybdenum (Mo) and tungsten (W) provide corrosion resistance; boron (B) enables glass formation; and rare earths such as yttrium (Y) lower critical cooling rate (CCR). The passive film stability of these Fe-based amorphous metal formulations have been found to be superior to that of conventional stainless steels, and comparable to that of Ni-based alloys, based on electrochemical measurements of the passive film breakdown potential and general corrosion rates.

Production of wide shear-rolled magnesium sheet for part forming

Magnesium is the lightest structural metal known: at approximately 1/5 the density of steel, 1/2 the density of titanium and 2/3 the density of aluminum. Hence magnesium alloys represent potential weight savings across the entire transportation industry. The major hurdle to the deployment of magnesium products by the transportation industry is the price barrier that exists due to the current high cost of producing magnesium alloy sheet on a volume basis. Proven technology (e.g., twin roll sheet casting and hot reversing coil mill technology) exists which could lower the cost of magnesium alloy sheet by as much as 50%, but needs to be demonstrated and implemented in high volume production to achieve benefits. In addition, the predominant basal texture (alignment of basal planes parallel to the sheet surface) that exists in magnesium alloy sheet results in poor low temperature formability resulting in added fabrication costs. Cost reduction achieved through energy efficiency, coupled with even greater energy savings by deployment of this lightest of metals, will help the United States achieve its goal to eliminate dependence on foreign fossil fuel. Oak Ridge National Laboratory (ORNL), Magnesium Elektron North America (MENA), and FATA Hunter collaborated on this project to develop shear rolling technology of magnesium sheet to enable improvement of the formability of magnesium sheet while addressing cost and lower energy consumption.