PowderMet          AMPM          Special Interest          TNT Presentations

014 - Study on Close-Coupled Gas Atomization (CCGA) Process : CFD Modelling via Discrete-Phase Model (DPM)
Jo Samuel Joseph Subramanian, University of Leeds

In the past decade, powder metallurgy has become increasingly vital to the Additive Layer Manufacturing (ALM) industry due to its broad applications. Among powder production methods, gas atomization remains the most effective. However, the process’s complexity—driven by rapid gas-melt interactions—makes understanding its underlying physics challenging, even with high-speed camera technology. This unpredictability results in larger particle sizes and a wide particle-size distribution (PSD), creating inefficiencies. The yield often falls below 35%, while out-of-specification powders require re-melting, doubling energy costs as the inert gas is recompressed.

This research utilizes Computational Fluid Dynamics (CFD) to analyze instabilities in the gas atomization process, focusing on the sub-ambient aspiration pressure formed at the melt nozzle tip and its effect on melt flow rate. User-Defined Functions (UDFs) were applied to couple aspiration pressure with melt flow rate, revealing significant process instabilities. Findings show that higher melt temperatures increase instability, further highlighting the process’s inherent randomness. Additionally, a new fluctuation pattern in the gas flow field was detected at elevated melt temperatures, which was not present at lower temperatures.

023 - Gas-Enabled Innovation in Powder Atomization
Eduardo Cardoso, Linde AG, Linde Inc.

As the technologies and use cases using high-quality metal powders continue to advance, studies have shown that gas atomization is the method of choice for producing this feedstock. Inert gases like argon or nitrogen are typically used to produce metal powders. These gases play a key role in delivering the desired product quality attributes such as particle size distribution and oxygen content. Fine-tuning the gas parameters can thus improve process robustness and help deliver powders with better sphericity, superior flowability and improved chemical purity. This miniaturization trend presents powder manufacturers with new challenges as finer particles with good morphology and high yield are more complex to produce. One way of meeting these challenges is by heating up the gas up to 750°F. Linde has researched the effect of hot gas and developed an instantaneous heating solution enabling a higher yield during powder production.

Another way of addressing these challenges is by establishing a deeper understanding of the underlying process and how the gas structure can affect the resulting powder morphology. Linde has developed a state-of-the-art atomization test bench to study the fundamentals of atomization in an industrial scale set-up. All relevant gas parameters like volume, pressure, temperature, and ranges of gas as well as different nozzle design can be tested. High speed cameras and schlieren imaging technology are used to visualize the mechanisms of decomposition during primary and secondary atomization.

027 - Investigation of Flow and Performance Anomalies in a Close-Coupled Gas Atomization Nozzle
Joseph Tunick Strauss, FAPMI, HJE Company, Inc.

There are several figures of merit used to quantify the performance of an atomization nozzle including gas/metal ratio and the yield of product produced. The operational characteristics of a nozzle can be quantified with the use of a gas/water flow bench, Schlieren imaging, and yield data from actual atomization runs.

Occasionally, it has been found that geometrically identical nozzles with equivalent gas flow rates will produce significantly different gas/metal ratios and product yield.

This study will investigate two geometrically identical nozzles to determine the cause of the disparity in their flow and performance characteristics.

003 - Iron Copper Manganese (FCM) PM Steel for PM Structural Parts
S. Sundar Sriram, Sundram Fastners Limited

Iron copper steels are commonly used for PM structural parts. Copper powder is either admixed in the blend or it is diffusion bonded. During sintering it melts at around 1083 C and flows between Iron powders particles and thereby promotes bonding between the powder particles which improves the strength of the part. In this is study , copper powder alloyed with manganese and other hardenability enhancing additives. The alloy design enables the copper alloy additive to at temperatures lower than that of Cu melting point enabling better diffusion at iron particle boundaries. Mn also contributes to increasing the hardenability. This proprietary alloy ensures that parts can be made with lesser copper content as compared to standard FC grades without compromising the mechanical properties. Sintered Mechanical properties FCM specimens are contrasted with FC specimens and presented in this study.

073 - Mechanical and Dynamic Properties of Sustainable Powder Metallurgy Alloy FL-5008
Roland Warzel III, North American Höganäs Co.

Sustainability is a growing trend within society and the automotive industry. Powder metallurgy (PM) is already recognized as a green technology which can address the sustainability requirements of current and future applications. A recently introduced lean chromium alloy was shown to provide similar mechanical performance to copper steel materials. This alloy also has a sustainability advantage over copper steels. For many applications, fatigue strength is a limiting factor and reliable fatigue data and models are important in selecting the best material system. In this paper, the mechanical properties of the recently standardized material FL-5008 will be presented. Additionally, fatigue data for the FL-5008 will be compared to copper steels and a fracture mechanics model will be presented to reliably predict the effect of density and stress concentrations on fatigue life.

068 - Enabling Next-Generation Fission and 1st Generation Fusion Energy via Powder Metallurgy Based Methods
Jordan Tiarks, Ames National Laboratory

Future nuclear energy platforms including next-generation fission and 1st generation fusion require advanced material solutions to meet the extreme temperatures, pressures, and high irradiation loads that define these environments. Powder metallurgy is a promising pathway for scalable manufacture of these advanced material solutions including oxide dispersion strengthened (ODS) ferritic steels, vanadium based structural materials, and refractory alloys, including concentrated refractory multi-principal-element alloys (CR-MPEA). This presentation will focus on powder-based efforts to design novel materials, to produce them in high quality powders, and to develop processing controls necessary to advance the state of the art in nuclear materials.

029 - Convergent Manufacturing Canisters for Powder Metallurgy – Hot Isostatic Pressing (PM-HIP) of 316L Stainless Steel
Pavan Ajjarapu, Oak Ridge National Laboratory

Techniques such as additive manufacturing (AM), powder metallurgy (PM), and hot isostatic pressing (HIP) are being explored to fabricate large-scale near net-shaped components However, each of these technologies have their own merits and drawbacks. This work demonstrates the feasibility of a combined AM + PM approach which benefits from the intrinsic advantages of both AM and PM-HIP. Powders of 316L stainless steel (SS) were filled in canisters fabricated via (1) conventional extrusion, (2) laser powder bed fusion (LPBF), and (3) blown powder directed energy deposition (BP-DED) before being degassed and subjected to HIPing. Further, a hybrid combination of laser hot wire DED and 5-axis CNC machining was used to manufacture a T-valve canister, followed by powder filling and HIPing. Post-HIP specimens were inspected for porosity, shrinkage, microstructure, and mechanical properties. This talk highlights the influence of canister fabrication technique on HIPed 316L powders, while showcasing the feasibility of manufacturing complex, large-scale rector pressure vessel (RPV) components via convergent manufacturing.

078 - Evaluating Bioinspired Designs for Metal Additive Manufacturing
Sundar Atre, University of Louisville

The present study focuses on the creation of innovative bioinspired structures guided by the mechanically resilient lattices found in deep-sea sponges. Sea sponges possess tubular skeletal structures constructed from silica or calcium carbonate, featuring interconnected channels and struts that imbue them with both mechanical stability and flexibility. The tubular structures also offer resistance to soil movement and stabilize foundation structures. Methods to 3D print two types of materials will be investigated: a plant-based resin and a stainless steel. The design will be varied to represent 3 length scales. The characterization of these structures will be investigated for dimensional fidelity and mechanical properties to understand the limits of features that can be accurately fabricated based on variations in material and 3D printing conditions. The study is expected to establish the feasibility of the combination of new materials, designs and manufacturing methods to study a new class of tubular metamaterials for transportation and medical applications.

106 - Low-Cost Additive Manufacturing of CP-Ti Component Using Optimized Photopolymer
Kansuda Kosolinsee, Loughborough University

This study explores an economical additive manufacturing strategy for metal parts using a commercial LCD printer, known for high resolution and surface quality. The precursor binders from a variety of acrylate resins were systematically optimised to create particle-filled suspensions that ensure good printability and strength during printing. A stable CP-Ti slurry with 50 vol% solid loading was prepared and analysed. Printing parameters were fine-tuned to produce a defect-free CP-Ti green body. The green specimen underwent thermal debinding to remove organic binder substances, followed by sintering under varied conditions to achieve a dense CP-Ti component. The impact of sintering profiles on microstructural and mechanical properties was extensively analysed. The research confirms demonstrated that vat photopolymerisation can successfully manufacture CP-Ti structures, with potential avenues for future development were discussed.

114 - The Repetitive Production of PM HIP Capsules Using a High-Pressure Hydroforming Technique
Ingemar Nygren, Quintus Technologies AB

A novel new high-pressure hydroforming technique using a flexible rubber diaphragm between the liquid pressure medium and the sheet metal will be presented. No seal is thus needed between the metal sheet and the pressure medium. A single lower tool half is required, and the diaphragm acts as a flexible upper tool half. Further, the flexible diaphragm allows for several tools to be used in one and the same forming operation. All kinds of sheet metal and thicknesses may be formed using the technique which is used in the PM HIP industry to produce capsules in various materials including carbon steel, nickel base alloys and titanium. Simulation of process provides reliable results with good accuracy using simulation software, and once a tool has been developed, repeatable production of components is made possible. This paper will detail how components can be manufactured which can later be welded together to form powder capsules of the same size and tolerance. The combination of forming and cutting in one and the same forming cycle, indicate a significant productivity increase.

111 - A Comparison of Plastic and Viscoplastic Models for Distortion Prediction in PM-HIP Process
Subrato Sarkar, Oak Ridge National Laboratory

Powder metallurgy hot isostatic pressing (PM-HIP) is an advanced manufacturing process that can efficiently produce near net shape parts with high material utilization and uniform microstructures. While the PM-HIP process is used frequently to produce small scale components, its application to large scale components is still limited due to inadequate understanding of its complex processes that cause unpredictable post-HIP shape distortions. A computational model can be a cost-effective alternative to exhaustive experimentation required to fully understand the PM-HIP process. However, a systematic approach to develop and use the computational models is still unavailable. Therefore, we present a comparison of plastic and viscoplastic models that are frequently used to model the PM-HIP process for distortion predictions. We compare the model parameters, calibration approach, experimental requirements and model performance under different conditions. We outline a systematic approach for choosing, calibrating and using a PM-HIP model for accurate shape distortion predictions.

519 - Transforming Combustible Dust Safety: The Impact of NFPA Standard 660
Doug Thomas, North American Höganäs Co.

On December 6, 2024, the National Fire Protection Association (NFPA) introduced the NFPA 660 Standard for Combustible Dusts and Particulate Solids. This comprehensive standard consolidates all existing combustible dust guidelines into a single framework. NFPA 660 establishes fundamental as well as industry-specific protocols for managing combustible dust, enhancing fire prevention measures, and promoting best practices to protect facilities from associated hazards, fires, and dust explosions. It encompasses key NFPA standards, including NFPA 61, NFPA 484, NFPA 652, NFPA 654, NFPA 655, and NFPA 664. This presentation aims to clarify the significant implications of NFPA 660 for industry professionals engaged in safety management, facility operations, and regulatory compliance, ensuring they are well-acquainted with the standards and their provisions. For information on the standard and revision cycle, please visit NFPA 660 Standard.