Article
Chemistry, Physical
Emad Maawad, Andreas Stark
Summary: TIMETAL (R) 54M is a relatively new (alpha + beta) Ti alloy with better machinability and forgeability compared to Ti-6Al-4V. Through in situ measurements using high energy synchrotron X-ray diffraction (HE-XRD) and a dilatometer setup, it was found that the temperature range of beta ->alpha phase transformation of Ti-54M during cooling at higher rates is larger than that of Ti-6Al-4V, resulting in different CCT diagrams.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Materials Science, Multidisciplinary
S. Y. Li, S. Y. Duan, W. Q. Ming, C. L. Wu, J. H. Chen
Summary: The S-phase is an effective strengthening precipitate in aluminum alloys for aerospace applications. Previous studies have well revealed its precipitation mechanism in AlCuMg alloys. However, this study reports a different scenario of S-phase formation in an AlCuLiMg alloy. By using atomic-resolution imaging in transmission electron microscopy, it is discovered that this alloy can form a precipitate microstructure dominated by Li-containing Guinier-Preston-Bagaryatsky zones and previously unknown S-like phase precipitates. The formation of the S-like precipitate undergoes a structural phase evolution rather than a conventional phase transformation. This study shows that AlCuLiMg alloys can develop a distinct microstructure with S-like/S-phase and T-1-phase precipitates, without the commonly observed delta'/theta'/delta' composite precipitates.
Article
Multidisciplinary Sciences
Sridhar Niverty, Rajib Kalsar, Robert J. Seffens, Anthony D. Guzman, Timothy J. Roosendaal, Lyndi Strange, Vineet V. Joshi
Summary: A unique in situ multimodal corrosion system was developed in this study, which can acquire multiple types of information about the corrosion process. The corrosion behavior of different materials under different conditions was investigated using this system.
SCIENTIFIC REPORTS
(2023)
Article
Chemistry, Physical
Mariana C. M. Rodrigues, Thomas Garcin, Matthias Militzer
Summary: This study explores the potential of laser ultrasonics for metallurgy (LUMet) as an advanced in-situ technique to measure the alpha formation kinetics in a Ti-5553 alloy. Experimental observations and theoretical models based on the Johnson-Mehl-Avrami-Kolmogorov (JMAK) theory provide insights into transformation kinetics. The consistency between the partial time-temperature-transformation (TTT) diagram and in-situ measurements reaffirms the monitoring capacity of LUMet for microstructure evolution in Ti-alloys.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Thermodynamics
R. F. M. Santos, V. P. Ricci, C. R. M. Afonso
Summary: This study aims to obtain continuous cooling transformation (CCT) diagrams for metastable beta Ti-12Mo-6Zr-2Fe (TMZF) and stable beta Ti-40Nb alloys and analyze their microstructure, elastic modulus, and Vickers microhardness under varied cooling rates. The results show that with an increase in cooling rate, both alloys exhibit lower Vickers microhardness and elastic modulus values.
THERMOCHIMICA ACTA
(2022)
Article
Chemistry, Physical
Qiang Wang, Kang Zhang, Wenjuan Niu
Summary: Ti-Cu alloys were in-situ fabricated by SLM with different Cu contents, showing fine microstructure and improved mechanical properties with increasing Cu content. The enhancement in microhardness, yield strength and ultimate tensile strength can be attributed to multiple strengthening mechanisms.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Chemistry, Physical
Mateusz Morawiec, Anna Wojtacha, Marek Opiela
Summary: This study investigates the phase transformation kinetics of high strength low-alloy steel (HSLA) during continuous cooling. Experimental results show changes in microstructure, including ferrite, bainitic ferrite, and bainite, at different cooling rates. Increasing the cooling rate reduces the amount of retained austenite in the steel microstructure and affects its mechanical properties.
Article
Materials Science, Multidisciplinary
Joshua Collins, Martina Piemonte, Mark Taylor, Jonathan Fellowes, Ed Pickering
Summary: A model for predicting the continuous cooling transformation (CCT) behavior of low-alloy steels is developed by using semi-empirical expressions for isothermal transformation behavior and coupling them with Scheil's additivity rule. The proposed model incorporates novel modifications to improve CCT predictions, including a carbon-partitioning model, thermodynamic boundary conditions, and a Koistinen-Marburger expression for martensitic behavior.
Article
Chemistry, Physical
Junhao Zhao, Binbin Wang, Tong Liu, Liangshun Luo, Yanan Wang, Xiaonan Zheng, Liang Wang, Yanqing Su, Jingjie Guo, Hengzhi Fu, Dayong Chen
Summary: This study observed in situ formed quasicrystal (QC) phase in an Al-based alloy processed by Selective Laser Melting (SLM). The particle size of the QC phase processed by SLM was smaller compared to other methods, and the shape of the QC phase varied with solidification conditions. It was found that the formation of QCs was promoted and the growth of QC phase was effectively inhibited at higher cooling rates. The QC phase could transform into Al6Mn through aging, leading to improved mechanical properties. The results suggest that SLM is an ideal processing route for fabricating in situ QC-strengthened Al-based alloys.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Metallurgy & Metallurgical Engineering
A. M. A. Mohamed, Y. Zedan, A. M. Samuel, H. W. Doty, V. Songmene, F. H. Samuel
Summary: This study investigated the influence of trace elements Pb, Bi, and Sn on the microstructure and mechanical properties of Sr-modified and grain-refined Al-10.8%Si-2%Cu-based alloys. The addition of Pb had no significant effect on the microstructure, while Bi counteracted the modification effect of Sr and Sn precipitated on pre-existing phases. Sn and Bi reacted with Mg, but not with transition elements. High percentage of Sn may cause reduction in alloy strength due to the precipitation of soft beta-Sn phase particles.
INTERNATIONAL JOURNAL OF METALCASTING
(2023)
Article
Materials Science, Multidisciplinary
Yiqun Zhang, Junming Gou, Tianzi Yang, Yubin Ke, Tianyu Ma
Summary: A non-equilibrium time-temperature-transformation (TTT) diagram and the corresponding time-temperature-property (TTP) relation were determined for Fe73Ga27 alloy, which exhibits significantly enhanced magnetostriction with the formation of coherent L6(0) nanoprecipitates. The diagram provides a processing base for enhancing the magnetostriction of Fe-Ga alloys and can offer important guidance for tailoring the microstructure of other nanoprecipitates-bearing alloys with similar diffusion-controlled phase transformation.
Article
Nanoscience & Nanotechnology
P. Pandee, P. Sankanit, V. Uthaisangsuk
Summary: The structure-mechanical property relationships of an in-situ A356/Al3Zr composite were investigated through experiments and microstructure based modeling. The Al3Zr reinforcement was successfully formed in the cast composite material, improving the overall tensile strength but reducing the elongation. However, Sr modification resulted in a simultaneous enhancement of the tensile strength and ductility by reducing the size and aspect ratio of eutectic silicon. Microstructure based FE models were used to study the local stress and strain distributions and interactions between constitutive phases, providing insights into the formation of localized shear bands and potential crack sites.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Materials Science, Multidisciplinary
X. J. Jiang, S. J. . Bao, L. W. Zhang, X. . Y. Zhang, L. S. Jiao
Summary: In recent years, there has been increasing attention on the research and development of high strength Zirconium-Titanium (ZrTi) based alloy system. However, the increase in strength of ZrTi alloy leads to a significant decrease in plasticity, similar to other metallic materials. This study demonstrates the preparation of a high strength and toughness ZrTi alloy with gradient structure using laser surface remelting. The results show improved tensile strength of 1550 MPa and a tensile elongation above 10%, alongside the formation of a gradient structure from the surface to the matrix, which is attributed to the composite deformation mechanisms of dislocation slip, twinning, and stress-induced martensitic transformation.
Article
Materials Science, Multidisciplinary
X. J. Jiang, J. Bai, N. Yang, Q. X. Ran, S. Q. Wang
Summary: The preparation process of titanium alloys typically involves hot deformation and post heat treatment, with the formulation of the heat treatment process being based on the key factor of alpha-beta phase transformation temperature. Current study results indicate that the transformation temperature of alpha-beta phase changes significantly after hot deformation. The energy increase and phase stability decrease of the alpha and beta phase due to defects formed during hot deformation are the key reasons behind this phenomenon. Analysis by DSC and re-determination of phase transformation temperature according to different deformation processes are crucial for the heat treatment of titanium alloys.
Article
Materials Science, Multidisciplinary
N. R. Abdul Razak, X. F. Tan, F. Somidin, H. Yasuda, S. D. McDonald, K. Nogita
Summary: Observing TLP processes for rapid Cu6Sn5 growth using real-time synchrotron X-ray imaging helps address the issues of slow TLP process kinetics and uncontrolled void formation, providing important insights for the development of products suitable for high reliability and high-temperature applications.
