The Experts below are selected from a list of 600 Experts worldwide ranked by ideXlab platform
J Buha - One of the best experts on this subject based on the ideXlab platform.
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grain refinement and improved age hardening of mg zn alloy by a trace amount of v
Acta Materialia, 2008Co-Authors: J BuhaAbstract:Abstract A Microalloying Addition of V acts as an effective grain refiner of Mg–Zn alloy. V exhibits limited but noticeable solubility in solid magnesium alloyed with Zn. V is exceptionally effective in promoting the nucleation of precipitates during age hardening and it also markedly accelerates the kinetics of precipitation. A near-peak hardness value can be reached after only 4 h of ageing at 160 °C. A considerably higher number density of the precipitates forms in Mg–Zn–V alloy as compared to Mg–Zn, resulting in a doubling of the hardness increment produced by artificial ageing. The highest level of hardening is achieved by ageing at intermediate temperatures. Natural ageing in Mg–Zn–V alloy is notably accelerated compared to that of the binary alloy. The details of the mechanisms involved with grain refinement and enhanced nucleation of precipitates by V are yet to be clarified.
Yasuhiro Aruga - One of the best experts on this subject based on the ideXlab platform.
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comparative and complementary characterization of precipitate microstructures in al mg si li alloys by transmission electron microscopy energy dispersive x ray spectroscopy and atom probe tomography
Journal of Alloys and Compounds, 2015Co-Authors: Yuki Koshino, Masaya Kozuka, Shoichi Hirosawa, Yasuhiro ArugaAbstract:Abstract In this study, comparative and complementary characterization of precipitate microstructures by transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS) and atom probe tomography (APT) has been performed for Al–0.55 wt%Mg–0.89 wt%Si(–0.043 wt%Li) alloys aged at 433 K for 1.2 ks (under aging) and 36 ks (peak aging). Quantitative estimation of nanometer-scale clusters (nanoclusters) and β″ precipitates by TEM and APT revealed that Microalloying Addition of Li increases the size and number density of these Mg–Si aggregates, resulting in the enhanced age-hardening response. Positive evidence by APT for the segregation of Li suggests that heterogeneous nucleation of such Mg–Si aggregates with the aid of Li is attributed to the modified precipitate microstructures and thus improved mechanical strength of this alloy system.
Yuki Koshino - One of the best experts on this subject based on the ideXlab platform.
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comparative and complementary characterization of precipitate microstructures in al mg si li alloys by transmission electron microscopy energy dispersive x ray spectroscopy and atom probe tomography
Journal of Alloys and Compounds, 2015Co-Authors: Yuki Koshino, Masaya Kozuka, Shoichi Hirosawa, Yasuhiro ArugaAbstract:Abstract In this study, comparative and complementary characterization of precipitate microstructures by transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS) and atom probe tomography (APT) has been performed for Al–0.55 wt%Mg–0.89 wt%Si(–0.043 wt%Li) alloys aged at 433 K for 1.2 ks (under aging) and 36 ks (peak aging). Quantitative estimation of nanometer-scale clusters (nanoclusters) and β″ precipitates by TEM and APT revealed that Microalloying Addition of Li increases the size and number density of these Mg–Si aggregates, resulting in the enhanced age-hardening response. Positive evidence by APT for the segregation of Li suggests that heterogeneous nucleation of such Mg–Si aggregates with the aid of Li is attributed to the modified precipitate microstructures and thus improved mechanical strength of this alloy system.
Michele V Manuel - One of the best experts on this subject based on the ideXlab platform.
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the effect of indium Additions on mg li and mg li al alloys
Metallurgical and Materials Transactions A-physical Metallurgy and Materials Science, 2014Co-Authors: Ryan J Hooper, Zachary L Bryan, Michele V ManuelAbstract:It is known that BCC Mg-Li alloys offer the opportunity to realize both high specific strength and good ductility in a light weight alloy. The commonest Addition to this system is Al due to its solid solution-strengthening ability. This system is also known to precipitate a potent metastable phase that subsequently transitions to the equilibrium AlLi phase. There are other systems, Zn, Cd, and In, which are also known to precipitate a phase that is similar to the AlLi phase. Of these Additions, the phase-evolution characteristics associated with adding In to Mg-Li and Mg-Li-Al alloys are largely unknown. This article seeks to understand the phase transformation, microstructural evolution, and mechanical behavior of In Additions by systematically studying Mg-Li-In in contrast to Mg-Li-Al and Mg-Li-Al-In. This study represents an initial investigation of the Mg-Li-In system, while simultaneously determining Indium’s potential as a Microalloying Addition. It was found that in the compositional ranges under investigation, a metastable phase does form in each system, and at longer aging times, In3Li13 is found to precipitate. Commentary and insight are also provided with respect to precipitate nucleation and coarsening behavior.
Langelier Brian - One of the best experts on this subject based on the ideXlab platform.
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Effects of Ca and Ce on the Microstructure and Mechanical Properties of Mg-Zn Alloys
'University of Waterloo', 2013Co-Authors: Langelier BrianAbstract:The effects of Ca and Ce on the precipitation behaviour and microstructural characteristics of Mg-Zn based alloys are investigated by comprehensive multi-scale characterization and analysis. The elements Ca and Ce are chosen for their potential to enhance (a) precipitation hardening and (b) alloy texture and ductility, and are examined at both alloying and Microalloying (< 0.5 wt%) levels. When added individually to Mg-Zn, Ca is found to enhance precipitation, but Ce produces a generally adverse effect on the hardening response. A pre-ageing strategy is proposed to alleviate this negative effect of Ce. The highlight of this work is the double Microalloying Addition of Ce-Ca to Mg-Zn, as this combination and quantity proves to be the most effective at increasing the age-hardening response, and enhancing microstructural characteristics for improved ductility. Transmission electron microscopy analysis reveals the hardening increase to originate from a refined precipitate microstructure, and the formation of fine-scale basal plate precipitates. These fine precipitates form during early ageing as monolayer GP zones consisting of Ca and Zn. The formation of these GP zones is facilitated by the atomic size difference between those two solutes, and their observed tendency to co-cluster. The monolayer GP zones evolve to multi-layered forms in the peak-aged condition. These precipitates are observed to be uniformly distributed, even where apparent precipitate-free zones are observed for the Mg-Zn type phases in the grain boundary regions. Notably, the size of these precipitate-free zones for the Mg-Zn phases is also reduced in the Ce-Ca microalloyed samples, compared to the binary alloy. The Ce-Ca Microalloying Additions also promote grain refinement and a weakening of the basal textures, typical of conventional Mg-based alloys, compared to both Mg-Zn and Mg-Zn-Ce. As a result, the tensile behaviour of the alloys with Ce-Ca is similarly enhanced. Considering both the precipitation hardening capability and microstructural characteristics, it is concluded that the double Microalloying Additions of Ce-Ca can be considered as a new alloy design strategy to successfully achieve improvement in both the strength and ductility of Mg-Zn alloys