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Effect of Ti content on microstructures and mechanical properties of cast Al-2Li-2Cu-0.5Mg alloy

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China Foundry 2023年第3期20卷 179-188页

作者： You-jie Guo Dong-chen Yang Liang Zhang Guo-hua Wu Yi-xiao Wang Pei-sen Li Guang-xiao Ren Liang-bin Li Xun-man Xiong National Engineering Research Center of Light Alloy Net Forming and State Key Laboratory of Metal Matrix Composites School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China Shanxi Jianghuai Heavy Industry Co. Ltd.Jincheng 048000ShanxiChina Jiangxi Ganfeng Lithium Co. LtdXinyu 338004JiangxiChina

Ti is regarded as one of the promising grain refiners in cast Al-Li-Cu alloys,but few research works have been done on its independent role.In this study,the effect of Ti on the microstructure evolution and mechanical properties of cast Al-2Li-2Cu-0.5Mg base alloy was investigated.The results revealed that the grains can be prominently refined with the increase of Ti addition.After adding Ti,high density TiB_(2)-Al_(3)Ti composite particles with a low lattice misfit form as heterogeneous nucleation sites for the α-Al matrix.δ’(Al3Li) and T_(1)(Al_(2)CuLi) precipitates that provide enhanced strength are dominated in the alloys after T6 aging treatment.The average size of both δ’ and half-width of δ’-precipitation free zone(PFZ) decreases gradually with the increase of Ti content.This is because the higher binding energy between Ti atoms and vacancies limits the diffusion efficiency of Li atoms,and thus results in a higher ductility.Additionally,no nano-sized Al_(3)Ti or core-shell structure of Al_(3)(Li,Ti) particles are found.The tensile property test results indicate that the Al-2Li-2Cu-0.5Mg alloy achieves optimal properties after aging at 175 °C for 32 h when 0.15wt.% Ti is added.It exhibits a yield strength of 352±5 MPa,an ultimate tensile strength of 423±6 MPa,and an elongation of(3±0.4)%.These findings are expected to offer a reliable theoretical guidance for the industrial composition design of the Al-Li-Cu series cast alloys.

关键词： cast Al-Li-Cu alloy Ti content grain refiner mechanical property microstructure

grain and dendrite refinement of A356 alloy with Al-Ti-C-RE master alloy

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Rare Metals 2013年第1期32卷 12-17页

作者： Hong-Liang Zhao Jin-Sheng Yue Ya Gao Kang-Rong Weng College of Materials Science and Engineering Zhengzhou University

Commercial A356 alloy was refined with a homemade A1-5Ti-0.25C-2RE master alloy, and the microstructure and macrostructure of the refined alloy were investigated. The results show that the grain refining effect of A356 is poor by the addition level of 0.5 wt% master alloy, but when the level reaches 3.0 wt% the grain can get a satisfactory refining effect. Dendrite of A356 can be effectively refined by addition of 0.5 wt% master alloy; however, the refining effect is not significantly improved by further increasing the addition of master alloy. grain and dendrite refining effects are compared in this article, and the results show that the grain and dendrite exhibit different refining effects with the same addition level of master alloy. Dendrite is easier to reach the optimal refining effect than grain.

关键词： A1-Ti-C-RE A356 grain refiner Secondary dendrite arm spacing （SDAS）

grain Refining Performance of SHS Al-50TiC Master Alloys for Commercially Pure Aluminum

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Journal of Wuhan University of Technology(Materials Science) 2002年第3期17卷 13-16页

作者：严有为 HuazhongUniversityofScienceandTechnology

An Al 50wt%TiC composite was directly synthesized by self propagating high temperature synthesis (SHS) technology,and then was used as a grain refining master alloy for commercially pure aluminum.The microstructure and grain refining performance of the synthesized master alloy were emphatically investigated.The SHS master alloy only contained submicron TiC particles except for Al matrix.Moreover,TiC particles were relatively free of agglomeration. grain refining tests show that adding only 0.1 wt% of the master alloys to the aluminum melt could transform the structure of the solidified samples from coarse columnar grains to fine equiaxed grains (average grain size 120μm),and that this grain refining effectiveness could be maintained for almost 1.5h at 1003K. Therefore,it is concluded that the SHS master alloy is an effective grain refiner for aluminum and its alloys, and that it is highly resistant to the grain refining fading encountered with most grain refiners.

关键词： SHS Al TiC composite grain refiner microstructure grain refinement

grain refinement of Al-3.5FeNb-1.5C master alloy on pure Al and Al-9.8Si-3.4Cu alloy

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China Foundry 2018年第4期15卷 314-319页

作者： chinna apparao kummari anil kumar birru department of mechanical engineering national institute of technologyManipur 795004 India

The refinement potential of Al-3.5 Fe Nb-1.5 C master alloy on pure aluminium and Al-9.8 Si-3.4 Cu alloy has been investigated. Different amounts of Al-3.5 Fe Nb-1.5 C master alloy were added to estimate the optimal addition level. It was found that the addition of Al-3.5 Fe Nb-1.5 C grain refiner can promote significantly the refinement of grains in the pure aluminium, particularly at 0.1 wt.%, with the mean primary aluminium α-grain size reducing to 187±3 μm from about 1-3 mm. Similarly, the microstructural study of the Al-9.8 Si-3.4 Cu alloy die casting at different weight percentages(viz. 0.0 wt.%, 0.1 wt.% and 1.0 wt.%) of Al-3.5 Fe Nb-1.5 C master alloy shows that the Al-3.5 Fe Nb-1.5 C master alloy as a grain refiner is also acceptable for Al-Si cast alloys when the silicon content is more than 4 wt.%. As a result of inoculation with Al-3.5 Fe Nb-1.5 C master alloy, the average grain size of α-Al is reduced to 22±3 μm from about 71±3 μm and grain refining efficiency is not characterized by any visible poisoning effect, which is the major limitation in the grain refinement of Al-Si cast alloys by applying Al-Ti-B ternary master alloys. Mechanical properties such as ultimate tensile strength and yield strength are significantly improved by 9.6% and 9.7%, respectively.

关键词： casting Al-Si alloy Al-3.5Fe Nb-1.5C microstructure grain refiner Al3Nb NbC

Refining performance of Al–3Ti–0.2C–5Sr on A356 alloy and electron microanalysis of ternary Al–Ti–Sr phases

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Rare Metals 2017年第3期36卷 188-192页

作者： Hong-Liang Zhao Chuan-Bin Zhang Ya Gao Qi-Yan Sun Sun College of Materials Science and Engineering Zhengzhou UniversityZhengzhou 450002China Department of Mechanical and Electrical Engineering Xuchang Vocational Technical CollegeXuchang 461000China

The effect of Al-3Ti-0.2C-5Sr （wt%） grain refiner on the refining performance and modification of A356 alloy was investigated using optical microscope （OM）.The morphology and crystal structure of ternary Al-Ti-Sr phases in Al-3Ti-0.2C-5Sr refiner were analyzed by scanning electron microscopy （SEM） and transmission electron microscopy （TEM）.The results show that the ternary Al-Ti-Sr phases in Al-3Ti-0.2C-5Sr refiner can promote the grain refining efficiency of A356 alloy.The ternary Al-Ti-Sr phases co-exist in two morphologies,i.e.,blocky-like phase and surround-like phase,besides,which both have the same chemical composition of Al34Ti3Sr.The crystal structure of Al34TiaSr is face-centered cubic,and the lattice parameter is determined to be about 1.52 nm.

关键词： grain refiner Aluminum alloy AI-Ti-Srphase Microscopic morphology Crystal structure

Simulation and verification of core–shell MC carbide design in Fe–C–Ni–V–Ti steel

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Journal of Iron and Steel Research(International) 2021年第1期28卷 58-65页

作者： Chen‑chong Wang Chun‑guang Shen Zhen Zhang Wei Xu State Key Laboratory of Rolling and Automation School of Materials Science and EngineeringNortheastern UniversityShenyang 110819LiaoningChina

Thermodynamic theory was used to calculate the formation temperature and site fraction of MC carbides in Fe–C–Ni–V–Ti system.The calculation results showed the theoretical formation conditions of core–shell MC carbides.One-step and two-step heat treatment processes were used in Fe–C–Ni–V–Ti alloy to,respectively,obtain homogeneous and core–shell MC carbides,which was consistent with the thermodynamic calculation results.The transmission electron microscopy observations showed that the core–shell MC carbide obtained by the two-step heat treatment process contained homogeneous(Ti,V)C as the core and basically VC as the shell.The mechanical test results proved that compared with homogeneous MC carbides,core–shell MC carbides could improve the basic mechanical properties of the alloy because VC shell greatly increased the bonding strength and separation work of Fe/MC interface.Thus,the core–shell MC carbide with a VC shell structure can be a better grain refiner and can be used in steels with a high standard of fracture toughness.

关键词： Core–shell carbide Thermodynamic calculation Microstructure observation grain refiner Mechanical