Powder Metallurgical Components in High Performance Applications: On-Demand Oral Presentations
Sponsored by: TMS Powder Materials Committee
Program Organizers: Peng Cao, The University of Auckland; Hanadi Salem, American University in Cairo; Paul Prichard, Kennametal Inc.; Matthew Osborne, Global Advanced Metals; James Paramore, Texas A&M University
Friday 8:00 AM
October 22, 2021
Room: On-Demand Room 12
Location: MS&T On Demand
Session Chair: Peng Cao, University of Auckland
Cemented Carbides with Complex Binder Alloys: Yong Liu1; 1Central South University
Cemented carbides are important powder metallurgical tooling materials. Substitution of the traditional cobalt by other cheaper alloy elements is an emerging technology due to low-cost requirements. On the other hand, the fracture toughness of Co-lean cemented carbides should also be improved. The authors recently investigated the effect of using complex-alloy system, inclusing Fe, Co, Cr and Ni elements instead of single Co on the mechanical properties of cemented carbides, and showed possitive improvement of fracture toughness and wear resistance. It indicated that the microstructures of the new binder-WC systmen can be kept in binary phase region on the condition that the carbon content is carefully controlled, at the same time, WC grain sizes in a wide range have been tested for the applicability of new binders. The fracture mechansim, including the fracture toughness in the wake of cracks and their propagation process, was theoratical analysed.
Development of Eco-friendly POM Binder System for High Strength Ti-MIM: Keemi Lim1; Muhammad Hayat1; Peng Cao1; 1The University of Auckland
The particular challenges related to the use of titanium and its alloy processed by MIM are its high reactivity and sensitivity towards contamination. In a typical MIM process, selections of appropriate binder and later removal have demonstrated to be crucial in reducing the contamination problem. The aim of this paper focuses on the development of a catalytic binder system based on polyacetal for Ti-MIM. An inherent characteristic of this catalytic binder system is their low debinding temperature at approximately 120-150 °C, which is below the temperature where impurities uptakes initiate (~ 260 °C). In addition, the effectiveness of employing organic acid as a potential green catalyst for the removal of polyacetal binder is reported.
Fabrication of Titanium and Titanium Alloy Components by Thermomechanical Powder Consolidation: Deliang Zhang1; 1Northeastern University
Our study aims to produce titanium and titanium alloy components without involving melting and casting. One route is to turn the titanium sponge into titanium powder by a process such as hydrogenation and dehydrogenation (HDH) and use powder blending, compacting and powder compact forging and extrusion-forging to facilitate powder consolidation and forming to various shapes. In-situ alloying and composition homogenization also occurs rapidly during plastic deformation of powder particles. Titanium hydride powder can also be used, since in-situ dehydrogenation can occur during heating of the powder compact to the consolidation temperature. The residual hydrogen can assist formation of ultrafine structure which is beneficial to the mechanical properties. It has been found that good mechanical properties are obtained with Ti-6Al-4V(wt.%) and other alloys. This report will present the findings from our group in manufacturing high performance titanium alloy components by thermomechanical powder consolidation and discuss the underlying materials science principles.
High-strength Titanium Matrix Composites Reinforced with In Situ Polycarbosilane-derived TiC Particle: Xin Lu1; Yu Pan1; 1University of Science and Technology Beijing
Titanium matrix composites (TMCs) offer much improved strength, elastic modulus, and wear resistance at both room and elevated temperatures, meeting the increasing demand for high-performance light-weight structural materials. In this work, we developed a powder conditioning process that involves coating polycarbosilane (PCS) on Ti particles. After sintering, the conditioned Ti powder was converted into Ti composites. TiC was derived from the pyrolysis of PCS and forming an in-situ reinforcement. The average grain size of α-Ti decreases significantly from 100.5 μm in pure Ti to 16.1 μm in the Ti-3 wt.% PCS composite. Among these Ti composites, the 3 wt.% PCS sample exhibits a high room temperature tensile strength of 861 MPa, high yield strength of 754 MPa and reasonably large elongation of 10.8%, respectively. This work would shed light on the design of low-cost and high-performance material with in-situ reinforcement.
Microstructural Uniformity duringSsintering, Thermal-plastic Processing and Recrystallization of Tungsten: Lin Zhang1; Xingyu Li1; Xuanhui Qu1; 1University of Science and Technology Beijing
Tungsten (W) is applied as the key components for modern electronics and coating technology and other industries. Processing such a refractory metal at high-temperature conditions (sintering, thermal-plastic deformation and heat treatments), ubiquitously results in W having heterogeneous behaviors in densification, grain growth, plastically response and recrystallization, giving rise to a non-uniform microstructural evolution. Microstructural uniformity and the possible effect of impurities make it both challenging and fundamentally critical for understanding basic properties and applications. This work starts by presenting polycrystalline W with different purity, aiming to study the microstructural and mechanical evolution during sintering, hot-rolling and recrystallization, and the possible effect of contaminated impurities on them. Further, it provides a fully densified bulk W with uniform microstructure and ~200 nm grain size by a simple pressureless two-step sintering method.
Thermodynamic Model for Predicting the Embodied Energy of Titanium Alloys Produced by Powder Metallurgy: James Paramore1; Brady Butler1; Matthew Dunstan1; 1US Army Research Laboratory
A thermodynamic model will be presented for predicting the embodied energy and carbon footprint of titanium alloys (e.g. Ti-6Al-4V) produced by a press-and-sinter powder metallurgy process. The final step of the modeled process is continuous belt sintering. However, the mass/energy balance and parasitic energy losses were modeled for the entire PM process from powder preparation to compaction and sintering, including the embodied energy of consumables. Theoretical values were produced via thermodynamic calculations, and these values were then adjusted for efficiency based on literature values of the various processes and equipment. Therefore, the energy efficiency and cost-effectiveness of the entire process on a commercial scale was evaluated. The current model focuses on a hydrogen sintering process for producing titanium alloys developed by the authors, but the model has been developed to be adaptable to various press-and-sinter processes and alloys.
Synthesis of Low-oxygen Titanium towards Achieving Strength-ductility Synergy: Kumar Jena1; Ying Xu1; Peng Cao1; 1University Of Auckalnd
The strength of Titanium increases monotonically with oxygen, accompanied by a drastic reduction in ductility. This trade-off between strength and ductility can be overcome by intentionally deploying rare earth nano oxides in an otherwise low-oxygen Titanium. The seemingly distinct strategy offers a design pathway towards achieving strength-ductility synergy in metallic Titanium. The first step is to synthesise high purity titanium powder with an oxygen content lower than 500 ppm. This paper presents a bottom-up approach for synthesizing such powder and reports the preliminary results.
Synthesis, Sintering and Mechanical Behavior of Ultra-fine Low-oxygen Titanium Powder: Ying Xu1; Kumar Jena1; Peng Cao1; 1The University of Auckland
Titanium powder play an important role in powder metallurgy and metal injection molding. The design and development of titanium with good ductility and ultrahigh strength for demanding applications have attracted much attentions over the years. Low-oxygen ultra-fine titanium particles were direct synthesized via a facile room temperature chemical reduction method in solution phase. The fabricated spherical titanium powders are uniform with diameter lower than 10 nm, stabilized by various organic ligands. The sintering and mechanical behaviors of the titanium are further investigated
Effect of Manufacturing Parameters on Inoculated PM Tool Steel Properties: Randa Habib1; Ayman Elsayed1; Saiid Anwar1; Bahaa Salah1; Taha Mattar1; 1Central Metallurgical Research and Development Institute
This work aims at Manufacturing of AISI H13 hot work tool steels with nano-inoculants by powder metallurgy and studying the effect of addition of nano-inoculants and heat treatments on the microstructure, the physical and mechanical propertiesof AISI H13 hot work tool steels. AISI H13 hot work tool steel is manufactured by powder metallurgy with the inoculation with Cu-coated Si3N4 nano particles and using Sn and Ni nano powders. The heat treatments are performed to harden the material by changing the structure from austenite to a fully hardened and tempered martensite. The results showed that VC6 is the most proper carbide that can be observed in the martensite matrix after hardening regime as the vanadium content of H13 tool steel is much sufficient to form more stable carbides. Tempered martensite with less fraction of eutectic carbides are observed in both H13 tool steel either without or with inoculation.
Selective Laser Melting of Metallic Glass Powder to Improve Chemical and Mechanical Performance of Magnesium: Xiyu Yao1; 1Southern University of Science and Technology
The poor corrosion resistance of magnesium (Mg) is one of the main problems that restrict its large-scale application. In this paper, Fe-based metallic glass layer was prepared on the surface of the magnesium substrate by using the selective laser melting (SLM) technique and an Fe-based metallic glass powder. The layers and the substrate formed a good mechanical bond, and it maintained amorphous state after laser melting. The corrosion rate of the substrate Mg was reduced from 0.89 mm/a to 0.11 mm/a.The surface wettability of the metallic glass layers were also better than that of the magnesium substrate, which was conducive to the adhesion of cells on the surface of the metallic glass. Cell toxicity test experiments showed that the degradation products of metallic glass were not toxic to cells. This new treatment method provides a solution for improving the corrosion resistance and mechanical performance of Mg and Mg alloys.