scholarly journals Rare-earth- and aluminum-free, high strength dilute magnesium alloy for Biomedical Applications

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Md Ershadul Alam ◽  
Soupitak Pal ◽  
Ray Decker ◽  
Nicholas C. Ferreri ◽  
Marko Knezevic ◽  
...  
Keyword(s):  
Rare Earth ◽  
Biomedical Applications ◽  
High Strength ◽  
Atom Probe ◽  
Mg Alloys ◽  
Transmission Electron ◽  
High Resolution Tem ◽  
Free Magnesium ◽  
Dilute Alloy ◽  
Strength And Ductility

Abstract Lightweight, recyclable, and plentiful Mg alloys are receiving increased attention due to an exceptional combination of strength and ductility not possible from pure Mg. Yet, due to their alloying elements, such as rare-earths or aluminum, they are either not economical or biocompatible. Here we present a new rare-earth and aluminum-free magnesium-based alloy, with trace amounts of Zn, Ca, and Mn (≈ 2% by wt.). We show that the dilute alloy exhibits outstanding high strength and high ductility compared to other dilute Mg alloys. By direct comparison with annealed material of the same chemistry and using transmission electron microscopy (TEM), high-resolution TEM (HR-TEM) and atom probe tomography analyses, we show that the high strength can be attributed to a number of very fine, Zn/Ca-containing nanoscale precipitates, along with ultra-fine grains. These findings show that forming a hierarchy of nanometer precipitates from just miniscule amounts of solute can invoke simultaneous high strength and ductility, producing an affordable, biocompatible Mg alloy.

Influence of Rare Earth Elements in Magnesium Alloy - A Mini Review

2020 ◽  
Vol 979 ◽  
pp. 162-166
Author(s):  
N. Sivashanmugam ◽  
K. L. Harikrishna
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Magnesium Alloys ◽  
Biomedical Applications ◽  
High Strength ◽  
Alloy System ◽  
Damping Capacity ◽  
Specific Strength ◽  
Large Size ◽  
Strength And Ductility

In recent days, the use of Magnesium and its alloys is preferred in defence, automotive and aerospace industries where large size and complex components are required in light weight. Besides, magnesium alloys are used in computers, electronic devices and biomedical applications. Alloying magnesium with rare earth elements (RE) is used to develop the light alloys for the stated applications at elevated temperature. Rare earth magnesium alloys are having unique properties over other metals, including a high specific strength, low thermal conductivity, good damping capacity and good castability. In this review article, the recent development of rare earth magnesium alloys will be reviewed from the view point of novel alloying designs. It has been revealed that in ternary alloy system Mg-ZN-RE alloy exhibited high strength and ductility. This leads the researchers to investigate Mg-ZN-RE alloy recently.

scholarly journals Modulation of Multiple Precipitates for High Strength and Ductility in Al-Cu-Mn Alloy

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7383
Author(s):  
Linxiang Liu ◽  
Zhijun Wang ◽  
Qingfeng Wu ◽  
Zhongsheng Yang ◽  
Kexuan Zhou ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Tensile Strength ◽  
High Strength ◽  
Mechanical Behaviors ◽  
High Tensile Strength ◽  
Transmission Electron ◽  
Evolution Pattern ◽  
Elongation To Failure ◽  
High Elongation ◽  
Strength And Ductility

The category and morphology of precipitates are essential factors in determining the mechanical behaviors of aluminum alloys. It is a great challenge to synthetically modulate multiple precipitates to simultaneously improve strength and ductility. In the present work, by optimizing the precipitations of the GP zone, θ’-approximant and θ’ phase for an Al-Cu-Mn alloy, a high tensile strength of 585 MPa with large elongation of 12.35% was achieved through pre-deformation and aging. The microstructure evolution pattern was revealed by detailed characterizations of scanning electron microscopy and transmission electron microscopy. It was found that such high tensile strength of the samples was due to a combination of strengthening by the high density of dispersive fine precipitates and dislocations, and the high elongation to failure was primarily attributed to the multimodal precipitates and elimination of precipitation-free zones along the grain boundaries. The strategy proposed here is a promising way of preparing ultra-strong Al-Cu-Mn alloys.

scholarly journals Development of low-alloyed and rare-earth-free magnesium alloys having ultra-high strength

2018 ◽  
Vol 149 ◽  
pp. 350-363 ◽  
Author(s):  
Hucheng Pan ◽  
Gaowu Qin ◽  
Yunmiao Huang ◽  
Yuping Ren ◽  
Xuechao Sha ◽  
...  
Keyword(s):  
Rare Earth ◽  
Magnesium Alloys ◽  
High Strength ◽  
Free Magnesium

scholarly journals Strengthening of a Near β-Ti Alloy through β Grain Refinement and Stress-Induced α Precipitation

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4255 ◽  
Author(s):  
Wei Chen ◽  
Chao Li ◽  
Kangtun Feng ◽  
Yongcheng Lin ◽  
Xiaoyong Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
High Strength ◽  
Ti Alloy ◽  
Β Phase ◽  
Ti Alloys ◽  
Α Phase ◽  
Transmission Electron ◽  
Strength And Ductility ◽  
Α Particles

Near β-Ti alloys with high strength and good ductility are desirable for application in aviation and aerospace industries. Nevertheless, strength and ductility are usually mutually exclusive in structural materials. Here we report a new thermo-mechanical process, that is, the alloy was cross-rolled in β field then aged at 600 °C for 1 h. By such a process, a high strength (ultimate tensile strength: 1480 MPa) and acceptable ductility (elongation: 10%) can be simultaneously achieved in the near β-Ti alloy, based on the microscale β matrix and nanoscale α phase. The microstructure evolution, mechanical properties and strengthening mechanisms have been clarified by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that the grain size of the β phase progressively decreased with the increasing of rolling reduction. Moreover, dense dislocation structures and martensite phases distributed in the cross-rolled β matrix can effectively promote the precipitation of nanoscale α particles. TEM analyses confirmed that a heat-treatment twin was generated in the newly formed α lath during aging. These findings provide insights towards developing Ti alloys with optimized mechanical properties.

Nano-Scale Analysis of Nano-Bainite Formed in Advanced High Strength Steels

2010 ◽  
Vol 654-656 ◽  
pp. 102-105 ◽  
Author(s):  
Ilana B. Timokhina ◽  
Hossein Beladi ◽  
Xiang Yuan Xiong ◽  
Elena V. Pereloma ◽  
Peter D. Hodgson
Keyword(s):  
High Strength Steels ◽  
High Strength ◽  
Atom Probe ◽  
Isothermal Treatment ◽  
Scale Analysis ◽  
Advanced High Strength Steels ◽  
Transmission Electron ◽  
High Alloyed Steel ◽  
Optimum Chemical ◽  
Lower Carbon

The effect of composition and processing schedule on the microstructure of C-Mn-Si-Mo-(Al)-(Nb) steels containing nano-bainite was studied using transmission electron microscopy (TEM) and atom probe tomography (APT). The major phase formed in all steels was nano-bainite. However, the steels with lower carbon and alloying addition content subjected to TMP had better mechanical properties than high alloyed steel after isothermal treatment. The presence of ferrite in the microstructure can improve not only ductility but lead to the formation of retained austenite with optimum chemical stability.

scholarly journals Nanostructure Characteristics of Al3Sc1−xZrx Nanoparticles and Their Effects on Mechanical Property and SCC Behavior of Al–Zn–Mg Alloys

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1909
Author(s):  
Ying Deng ◽  
Ziang Yang ◽  
Guo Zhang
Keyword(s):  
Mechanical Property ◽  
Grain Boundaries ◽  
Dissolution Kinetics ◽  
Lattice Misfit ◽  
High Strength ◽  
Atom Probe ◽  
Dark Field ◽  
Mg Alloys ◽  
High Angle ◽  
Scanning Transmission

The Nanostructure characteristics of Al3Sc1−xZrx nanoparticles and their effects on the mechanical properties and stress corrosion cracking (SCC) behavior of Al–Zn–Mg alloys were investigated by 3D atom probe analyses, high-angle annular-dark-field scanning transmission electron microscopy methods, electron back scattered diffraction techniques, electrochemical measurements, slow strain rate tests and quantitative calculations. The results show that adding small amounts of scandium (0.10 percent by weight) and zirconium into Al–Zn–Mg extrusion bars can precipitate Al3Sc1−xZrx nanoparticles with a number density of (7.80 ± 3.83) × 1021 per cubic meter. Those particles, with a low lattice misfit with matrix (1.14 ± 0.03 percent) and stable core-shell L12-nanostructure in aged Al–Zn–Mg alloys, can increase the yield strength by 161 ± 7 MPa via strong Orowan strengthening (the theoretical calculated value is 159 MPa) and weak Hall-Petch strengthening (the theoretical calculated value is 6 MPa). Moreover, Al3Sc1−xZrx nanoparticles can change the fracture mechanism of alloys in 3.5% NaCl solution from intergranular cracks to transgranular failure, and decrease the proportion of high-angle grain boundaries from 87% to 31%, thus reducing the microchemistry differences around the grain boundaries and anodic dissolution kinetics, and improving intergranular SCC resistance and ductility. This study offers a new approach to the simultaneous improvement in mechanical property and corrosion performance of high strength alloys.

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