scholarly journals Microstructure, Mechanical Properties and Corrosion Behaviors of Al–Li–Cu–Mg–Ag–Zn Alloys

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 443
Author(s):  
Mingdong Wu ◽  
Daihong Xiao ◽  
Xinkai Wang ◽  
Lanping Huang ◽  
Wensheng Liu

Combined with microstructure characterization and properties tests, the effects of Zn contents on the mechanical properties, corrosion behaviors, and microstructural evolution of extruded Al–Li–Cu–Mg–Ag alloys were investigated. The results show that the increase in Zn contents can accelerate hardening kinetics and improve the hardness of peak-aged alloys. The Zn-added alloys present non-recrystallization characteristics combined with partially small recrystallized grains along the grain boundaries, while the T1 phase with finer dimension and higher number density could explain the constantly increasing tensile strength. In addition, increasing Zn contents led to a lower corrosion current density and a shallower maximum intergranular corrosion depth, thus improving the corrosion resistance of the alloys. Zn addition, distributed in the central layer of T1 phases, not only facilitates the precipitation of more T1 phases but also reduces the corrosion potential difference between the T1 phase and the matrix. Therefore, adding 0.57 wt.% Zn to the alloy has an excellent combination of tensile strength and corrosion resistance. The properties induced by Zn under the T8 temper (solid solution treatment + water quenching + 5% pre-strain+ isothermal aging), however, are not as apparent as the T6 temper (solid solution treatment + water quenching + isothermal aging).

2011 ◽  
Vol 686 ◽  
pp. 253-259
Author(s):  
Xu Ning ◽  
Wei Dong Xie ◽  
Chun Mei Dang ◽  
Xiao Dong Peng ◽  
Yan Yang ◽  
...  

A series of Mg-6Al-2Sr-1.5Y-xNd (x=0, 0.3, 0.6, 0.9, 1.2) alloy samples were prepared and their microstructures were observed and mechanical properties were measured. The existing forms of Y and Nd were studied. The effects of Y and Nd on microstructure and mechanical properties of AJ62 alloy were investigated. The results show that the main existing forms of Y and Nd in AJ62 alloy are Al2Y and Al2Nd. The combined addition of rare earth Y and Nd can refine α-Mg matrix obviously and reduce the amount of the β-Mg17Al12phases; after solid solution treatment, the tensile strength of the alloys rise first and fall later with increasing content of Nd. When the content of Nd is about 0.6%wt, the values of tensile strengthes are up to the maximum both at room temperature and at 448 K.


2015 ◽  
Vol 816 ◽  
pp. 446-450
Author(s):  
Xiao Bing Zheng ◽  
Wen Bo Du ◽  
Ke Liu ◽  
Zhao Hui Wang ◽  
Shu Bo Li

The microstructure evolution of the Mg-3Zn-0.5Er-0.5Al (mass fraction, %) alloy under the different condition was investigated. The results showed that as-cast Mg-3Zn-0.5Er-0.5Al alloy mainly consisted of primary large irregular Mg4Zn7 phase and needlelike (Mg, Zn, Er, Al) quaternary phase. Mg4Zn7 phase almost dissolved into the matrix after solid solution treatment at 400 oC for 10 h, while the (Mg, Zn, Er, Al) quaternary phase still existed. The solution treated alloy was extruded at 250 °C. The ultimate tensile strength of the as-extruded alloy was approximately 268 MPa and the YTS was approximately 163 MPa companying with an elongation of 28%. The tensile strength of the as-extruded alloy improved obviously, which was mainly attributed to the grain refinement.


2011 ◽  
Vol 189-193 ◽  
pp. 1212-1217 ◽  
Author(s):  
Lian Zheng Ding ◽  
Qing Sen Meng ◽  
Zhong Wei Yang ◽  
Gang Wang

In this study, welding of 2205 duplex stainless steel was carried out by first using plasma arc welding as root welding and then using tungsten inert-gas (TIG) welding and metal inert-gas (MIG) welding respectively as cover welding, Weldability of 2205 duplex stainless steel using two different the welding processes is investigated. Microstructure characteristics, mechanical properties, pitting corrosion resistance are made comparison between the weldment that is solution treated and that is not .Influence of heat input and the solid solution treatment on complex properties of welded joints is evaluated, and the solid solution treatment was conducted for both of the welded joints fabricated by the welding processes mentioned preciously.


2011 ◽  
Vol 117-119 ◽  
pp. 1315-1318 ◽  
Author(s):  
Shih Hsien Chang ◽  
Shih Chin Lee ◽  
Kuo Tsung Huang ◽  
Cheng Liang

The aim of this study is to explore alloy 718 that treated at an optimal HIP process, and then imposed various solid-solution temperatures and aging treatment. The experimental results indicated that Laves and δ precipitations obviously appeared within the grain boundary, under HIP treatment and lower solid-solution temperatures (940°C), which would result in poor mechanical properties. However, Laves and δ phase can be completely dissolved at 1020°C 1 hour solid-solution treatment. The tensile strength was increased to 1331.5 MPa, and elongation reached up to 6.1% under a 1020°C solid-solution and aging treatment. Increasing the solid-solution temperature to 1060°C would cause parts of the NbC to dissolve, thus a large number of the thin sheet-shaped NbC would appear in the solid-solution and aging specimen. The yield stress is slight increase, but a lot of NbC precipitations will result in the decreasing tensile strength (1298.8 MPa) and elongation (5.4%). As a result, the optimal solid-solution treatment parameter of alloy 718 is 1020°C for 1-hour.


Metalurgi ◽  
2020 ◽  
Vol 35 (3) ◽  
pp. 105
Author(s):  
Moch Iqbal Zaelana Muttahar ◽  
Shinta Virdhian ◽  
Purbaja Adi Putra ◽  
Dagus Resmana Djuanda ◽  
Eva Afrilinda ◽  
...  

Al-Si alloys are being widely used as main engine components replacing iron in several parts in the automotive industry. Some of its mechanical properties were a reference in its alloy utilization. In this research, the heat treatment carried out on the specimen included solid solution treatment and the artificial aging process for aluminium alloys. Test pieces were heated on the furnace with a solid solution treatment process at 540 ° C with holding time around 5 hours and quenched at 60 °C with water quenchant, followed by 3 different aging treatment which included single-stage aging, artificial aging with pre-aged, and double stage aging. Tests carried out by hardness test, tensile strength test, impact test, metallographic and Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS) observations. The results of this research showed the differences in phase constituent and morphology microconstituents due to variations of aging. The difference of each treatment could be seen in the morphology of the precipitate that is dispersed, rounded and needle-like shaped, this phase can influence the mechanical properties of Al-Si-Cu alloys. The results of mechanical testing show the highest hardness was obtained by double stage aging treatment 161.27 HRB. The highest tensile strength occurs in specimens with a single-stage aging treatment of 202.56 MPa. The highest impact resistance occurred in samples with the pre-aging treatment of 18.6 J.


2021 ◽  
Vol 1023 ◽  
pp. 45-52
Author(s):  
Xiao Yan Wang ◽  
Meng Li ◽  
Zhi Xun Wen

After solid solution treatment at 1335°C for 4 hours and cooling to room temperature at different rate, the nickel-based single crystal superalloy were made into three kinds of nickel-based single crystal superalloy materials containing different size γ′ phases, respectively. The tensile test of I-shaped specimens was carried out at 980°C, and their effect of γ′ phase microstructure on the tensile properties was studied. The results show that the yielding strength of the material air-cooled to room temperature was lower than that with cooling rate at 0.15°C/s, but both of them were lower than the yielding strength of original material. Little difference was found on the elastic modulus of I-shaped specimens made of three kinds of materials. When the cubic degree of the γ′ phase is higher and the size is larger, the tensile properties of the material is better, which can be attributed to the larger size and narrower channel of the matrix phase that lead to higher dislocation resistance.


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