Effect of Al on the microstructure, corrosion behavior and mechanical properties of Mg-4Li

2020 ◽  
Vol 67 (1) ◽  
pp. 31-37
Author(s):  
Cheng Zhang ◽  
Liang Wu ◽  
Zilong Zhao ◽  
Guangsheng Huang ◽  
Bin Jiang ◽  
...  

Purpose This paper aims to investigate microstructure, corrosion behavior and mechanical properties of Mg-4Li and Mg-4Li-3Al. Design/methodology/approach The microstructure was characterized by using scanning electron microscopy and electron backscatter diffraction. The corrosion behaviors were measured by hydrogen evolution and potentiodynamic polarization tests. The mechanical properties were evaluated by tensile tests. Findings The addition of Al results in the precipitation of some Mg-Al phase and Al3Li phase particles, and the formation of some fine recrystallized grains. Originality/value Mg-4Li-3Al showed a higher corrosion rate than that of Mg-4Li, attributed to the precipitate particles in Mg-4Li-3Al causing microgalvanic corrosion and the change of grain orientation. The addition of 3 Wt. per cent Al increased the tensile strength by solid solution strengthening, precipitation strengthening, refinement strengthening and texture strengthening, whilst the elongation decreased by almost half.

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 238
Author(s):  
Sujung Son ◽  
Jongun Moon ◽  
Hyeonseok Kwon ◽  
Peyman Asghari Rad ◽  
Hidemi Kato ◽  
...  

New AlxCo50−xCu50−xMnx (x = 2.5, 10, and 15 atomic %, at%) immiscible medium-entropy alloys (IMMEAs) were designed based on the cobalt-copper binary system. Aluminum, a strong B2 phase former, was added to enhance yield strength and ultimate tensile strength, while manganese was added for additional solid solution strengthening. In this work, the microstructural evolution and mechanical properties of the designed Al-Co-Cu-Mn system are examined. The alloys exhibit phase separation into dual face-centered cubic (FCC) phases due to the miscibility gap of the cobalt-copper binary system with the formation of CoAl-rich B2 phases. The hard B2 phases significantly contribute to the strength of the alloys, whereas the dual FCC phases contribute to elongation mitigating brittle fracture. Consequently, analysis of the Al-Co-Cu-Mn B2-strengthened IMMEAs suggest that the new alloy design methodology results in a good combination of strength and ductility.


2012 ◽  
Vol 706-709 ◽  
pp. 2788-2793 ◽  
Author(s):  
Dmitry Orlov ◽  
Rimma Lapovok ◽  
László S. Tóth ◽  
Ilana B. Timokhina ◽  
Peter D. Hodgson ◽  
...  

In the present study, the effects of kinematic and geometric asymmetries in rolling during multi-pass processing of IF steel are examined. The theoretical investigation by final element simulations and experimental investigations by means of electron-backscatter diffraction analysis and tensile tests suggest that asymmetric rolling increases the total imposed strain compared to symmetric rolling, and largely re-distributes the strain components due to additional shear. This enhances the intensity of grain refinement, strengthens and tilts crystallographic orientations, and increases mechanical strength. The effect is highest in the asymmetric rolling with differential roll diameters.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shohei Ueki ◽  
Yoji Mine ◽  
Kazuki Takashima

AbstractMeteoric iron is the metal that humans first obtained and used in the earliest stage of metal culture. Advances in metallographic analysis techniques have revealed that meteoric iron largely comprises kamacite, taenite, and cohenite, which correspond to ferrite, austenite, and cementite in artificial steel, respectively. Although the mechanical properties of meteoric irons were measured previously to understand their origin and history, the genuine mechanical properties of meteoric iron remain unknown because of its complex microstructure and the pre-existing cracks in cohenite. Using micro-tensile tests to analyse the single-crystalline constituents of the Canyon Diablo meteorite, herein, we show that the taenite matrix exhibits excellent balance between yield strength and ductility superior to that of the kamacite matrix. We found that taenite is rich in nitrogen despite containing a large amount of nickel, which decreases the nitrogen solubility, suggesting that solid-solution strengthening via nitrogen is highly effective for the Fe–Ni system. Our findings not only provide insights for developing advanced high-strength steel but also help understand the mysterious relationship between nitrogen and nickel contents in steel. Like ancient peoples believed that meteoric iron was a gift from the heavens, the findings herein imply that this thought continues even now.


2011 ◽  
Vol 409 ◽  
pp. 639-644 ◽  
Author(s):  
Abdul Wadood ◽  
Tomonari Inamura ◽  
Hideki Hosoda ◽  
Shuichi Miyazaki

In order to develop new nickel-free biomedical Ti-based alloys, effect of silver additions on mechanical properties of Ti-5Cr (mol%) alloy was investigated. Cold workability of Ti-5Cr alloy was 5% in thickness reduction and the cold rolling reduction was improved to be 38% by 2mol% Ag addition and 96% by 4mol%Ag addition. The improvement was due to β phase stabilization. From the XRD results, α’ martensite was the dominant phase in Ti-5Cr-2Ag alloy and β phase was the dominant phase in Ti-5Cr-4Ag alloy. By tensile tests, Ti-5Cr-4Ag alloy showed good strength of 447 MPa in ultimate tensile strength (UTS) and ductility of 13% in fracture strain. Ti-5Cr-4Ag showed higher hardness of HV398 than Ti-5Cr-2Ag with HV288. The hardening by increase of Ag is probably due to the solid solution strengthening. By the cyclic loading-unloading tensile tests with a constant strain increment, Ti-5Cr-4Ag showed pseoudoelastic behavior. Ti-5Cr-4Ag also showed shape memory effect with 57% in shape recovery ratio. It is concluded that Ti-5Cr-4Ag is hopeful as a new non-allergic shape memory material for biomedical applications.


Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 112
Author(s):  
Unai Mayo ◽  
Nerea Isasti ◽  
José M. Rodríguez-Ibabe ◽  
Pello Uranga

Intercritically deformed steels present combinations of different types of ferrite, such as deformed ferrite (DF) and non-deformed ferrite (NDF) grains, which are transformed during the final deformation passes and final cooling step. Recently, a grain identification and correlation technique based on EBSD has been employed together with a discretization methodology, enabling a distinction to be drawn between different ferrite populations (NDF and DF grains). This paper presents a combination of interrupted tensile tests with crystallographic characterization performed by means of Electron Backscatter Diffraction (EBSD), by analyzing the evolution of an intercritically deformed micro-alloyed steel. In addition to this, and using the nanoindentation technique, both ferrite families were characterized micromechanically and the nanohardness was quantified for each population. NDF grains are softer than DF ones, which is related to the presence of a lower fraction of low-angle grain boundaries. The interrupted tensile tests show the different behavior of low- and high-angle grain boundary evolution as well as the strain partitioning in each ferrite family. NDF population accommodates most of the deformation at initial strain intervals, since strain reaches 10%. For higher strains, NDF and DF grains behave similarly to the strain applied.


Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1677
Author(s):  
Hooi Peng Lim ◽  
Willey Yun Hsien Liew ◽  
Gan Jet Hong Melvin ◽  
Zhong-Tao Jiang

This paper reviews the phase structures and oxidation kinetics of complex Ti-Al alloys at oxidation temperatures in the range of 600–1000 °C. The mass gain and parabolic rate constants of the alloys under isothermal exposure at 100 h (or equivalent to cyclic exposure for 300 cycles) is compared. Of the alloying elements investigated, Si appeared to be the most effective in improving the oxidation resistance of Ti-Al alloys at high temperatures. The effect of alloying elements on the mechanical properties of Ti-Al alloys is also discussed. Significant improvement of the mechanical properties of Ti-Al alloys by element additions has been observed through the formation of new phases, grain refinement, and solid solution strengthening.


2015 ◽  
Vol 817 ◽  
pp. 307-311 ◽  
Author(s):  
Peng Chao Zhang ◽  
Jin Chuan Jie ◽  
Yuan Gao ◽  
Tong Min Wang ◽  
Ting Ju Li

The Cu-Cr and Cu-Cr-Ti alloy plates were prepared by vacuum melting and plastic deformation. The effect of slight Ti element on microstructure and mechanical properties of Cu-Cr alloy was discussed. The result shows that Cr particles with spherical shape precipitated from Cu matrix after aging. Plenty Ti atoms dissolved in the vicinity of Cr particles and there were still parts of solid solution Ti atoms in other regions. Improvements in peak hardness and softening resistance were achieved with the addition of Ti element in Cu-Cr alloy. The addition of 0.1 wt.% Ti element makes Cu-Cr alloy possess tensile strength of 565 MPa and hardness of 185.9 HV after aging at 450 °C for 120 min, which can be attributed to multiple strengthening mechanisms, i.e. work hardening, solid solution strengthening and precipitation strengthening.


2017 ◽  
Vol 23 (5) ◽  
pp. 869-880 ◽  
Author(s):  
Ying-Guo Zhou ◽  
Bei Su ◽  
Lih-sheng Turng

Purpose Although the feasibility and effectiveness of the fused deposition modeling (FDM) method have been proposed and developed, studies of applying this technology to various materials are still needed for researching its applicability, especially with regard to polymer blends and composites. The purpose of this paper is to study the deposition-induced effect and the effect of compatibilizers on the mechanical properties of polypropylene and polycarbonate (PP/PC) composites. Design/methodology/approach For this purpose, three different deposition modes for PP/PC composites with or without compatibilizers were used for the FDM method and tested for tensile properties. Also, parts with the same materials were made by injection molding and used for comparison. In addition, different deposition speeds were used to investigate the different deposition-induced effects. Furthermore, the behavior of the mechanical properties was clarified with scanning electron microscope images of the fracture surfaces. Findings The research results suggest that the deposition orientation has a significant influence on the mechanical behavior of PP/PC composite FDM parts. The results also indicate that there is a close relationship between the mechanical properties and morphological structures which are deeply influenced by compatibilization. Compared with injection molded parts, the ductility of the FDM parts can be dramatically improved due to the formation of fibrils and micro-fibrils by the deposition induced during processing. Originality/value This is the first paper to investigate a PP/PC composite FDM process. The results of this paper verified the applicability of PP/PC composites to FDM technology. It is also the first time that the deposition-induced effect during FDM has been investigated and studied.


2017 ◽  
Vol 23 (2) ◽  
pp. 295-304 ◽  
Author(s):  
AmirMahyar Khorasani ◽  
Ian Gibson ◽  
Moshe Goldberg ◽  
Guy Littlefair

Purpose The purpose of this study was to conduct various heat treatments (HT) such as stress relief annealing, mill annealing, recrystallization (α + β) annealing and β annealing followed by furnace cooling (FC) that were implemented to determine the effect of these on mechanical properties and the microstructure of selective laser melted and wrought samples. The mentioned annealings have been carried out to achieve the related standards in the fabrication of surgery implants. Design/methodology/approach In this paper, based on F2924-14 ASTM standard SLM and conventionally wrought parts were prepared. Then HT was performed and different characteristics such as microstructure, mechanical properties, macro-hardness and fracture surface for selective laser melted and wrought parts were analysed. Findings The results show that the high cooling rate in selective laser melting (SLM) generates finer grains. Therefore, tensile strength and hardness increase along with a reduction in ductility was noticed. Recrystallization annealing appears to give the best combination of ductility, strength and hardness for selective laser melted parts, whilst for equivalent wrought samples, increasing HT temperature results in reduction of mechanical properties. Originality/value The contributions of this paper are discussing the effect of different annealing on mechanical properties and microstructural evolution based on new ASTM standards for selective laser melted samples and comparing them with wrought parts.


2018 ◽  
Vol 47 (5) ◽  
pp. 396-405
Author(s):  
Abdul Azeem ◽  
Sharjeel Abid ◽  
Noman Sarwar ◽  
Shahzaib Ali ◽  
Ahsan Maqsood ◽  
...  

Purpose The purpose of this study is to improve the mechanical properties and reduce the stiffness/harshness of fabric associated with the pigment dyeing of textiles. Design/methodology/approach The fabric was pigment dyed with the addition of three different softeners and binders. The fabric was then analyzed to have improved textile properties by measuring tear strength, bending length, crocking and washing fastness tests. Findings The conventional route of pigment dyeing (without any softener) imparted poor mechanical and rubbing fastness. The softener-added recipe provided better mechanical, rubbing and washing fastness, and the stiffness values were oppressed as well. Practical implications Because of reduced stiffness, increased fastness and mechanical properties, the use of softener with pigment dyeing can improve the market values and satisfaction of the dyed fabrics. The finished product would also have better life and endurance. The process can be modified easily to have a better end-product with a negligible cost addition in industrial process, as softeners are cheap and used in low (10-20 g/l) in industrial settings without affecting the required shades. Originality/value This is the first report, to the best of the author’s knowledge, on the optimization of pigment dyeing of PC fabric with the addition of Helizarin and perapret softeners in dyeing bath.


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