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Improving microstructure and mechanical properties of Ti43Al5Nb0.1B alloy by addition of Fe

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Rare Metals 2019年第11期38卷 1024-1032页

作者： Yong Yang Rui-Run Chen Hong-Ze Fang jing-jie guo Hong-Sheng Ding Yan-Qing Su Heng-Zhi Fu School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China Department of Materials Engineering Baotou Vocational&Technical CollegeBaotou 014030China

Alloying additions of 0 at%-1.1 at% Fe were added into Ti43A1Nb0.1B alloys for increasing the roomtemperature strength and ductility,and the microstructure and mechanical properties were systematically *** results show that the lattice tetragonality(c/a) of γ phase and the average width of columnar grains of alloys decrease with Fe content *** addition brings about the formation of Fe-rich B2 phase both in the dendrites and in interdendritic regions,and its content increases with Fe contents ***,Fe addition aggravates the Al segregations in the interdendritic *** alloy with 0.7 at% Fe exhibits higher combined mechanical properties with the ultimate compression strength and fracture strain of 1958.4 MPa and 29.8%,*** grain refinement strengthening and solid-solution strengthening of Fe are responsible for the improvement in the strength and the ***,excessive Fe addition results in the decrease in the strength and strain,which is attributed to the severe A1 segregations in the interdendritic regions that cause the premature fracture during compression.

关键词： TiAl Fe B2 phase Microstructure Mechanical properties

Diversification of interfaces triggered hydrogen storage properties enhancement

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Rare Metals 2024年第5期43卷 2324-2330页

作者： Jia-Xin Zhang Xin Ding Rui-Run Chen Xiang-Feng Ma Wen-Chao Cao Yong Zhang jing-jie guo National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of TechnologyHarbin 150001China

Dual effects of grain refinement and alloying are achieved and the mechanism of"diverse interfaces reinforcement"for hydrogen storage Mg alloys is first *** interface reinforced Mg-Y-Zn-Al alloy for hydrogen storage is *** work figures out that the adventurous Al-rich phase exhibits an ordered face-centered cubic(FCC)structure with composition of(31±2)at%Y-(28±1)at%Zn-(41±3)at%Al,i.e.,Y_(3)Zn_(3)Al_(4),and an incoherent interface between Y3Zn3Al4phase and Mg substrate is observed.

关键词： hydrogen alloying alloy

Microstructure and properties of novel quinary multi-principal element alloys with refractory elements

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China Foundry 2015年第5期12卷 319-325页

作者： Na-na guo Liang Wang Yan-qing Su Liang-shun Luo Xin-zhong Li jing-jie guo Heng-zhi Fu National Key Laboratory for Precision Hot Processing of Metals School of Materials Science and Engineering Harbin Institute of Technology

Five equiatomic alloys(Ti Zr Hf VNb, Ti Zr Hf VTa, Ti Zr Nb Mo V, Ti Zr Hf Mo V and Zr Nb Mo Hf V) composed of five elements with high melting temperature, respectively were prepared by arc-melting to develop a novel high temperature alloy. The five alloys exhibit different dendritic and interdendritic morphologies. The Ti Zr Hf VNb, Ti Zr Hf VTa and Ti Zr Nb Mo V alloys formed disordered solid solution phases with body-centered cubic structure, and exhibited high compressive strength and good plasticity. The Ti Zr Hf Mo V and Zr Nb Mo Hf V alloys are composed with Laves phase(Hf Mo2) and disordered solid solution phases with body-centered cubic structure. The Ti Zr Hf Mo V and Zr Nb Mo Hf V alloys are harder and more brittle than the other three alloys due to the existence of hard and brittle Laves phases. At high temperatures, the strength decreases to below 300 MPa for the Ti Zr Hf VNb and Ti Zr Hf Mo V alloys. Solution strengthening is the primary strengthening mechanism of the Ti Zr Hf VNb, Ti Zr Hf VTa and Ti Zr Nb Mo V alloys, and brittle Laves phase is the main cause for the low ductility of the Ti Zr Hf Mo V and Zr Nb Mo Hf V alloys.

关键词： high temperature alloys high-entropy alloy crystal structure and microstructure hardness compressive property

Microstructures,micro-segregation and solidification path of directionally solidified Ti-45Al-5Nb alloy

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China Foundry 2016年第2期13卷 107-113页

作者： Liang-shun Luo Tong Liu Kun Li Yan-qing Su jing-jie guo Heng-zhi Fu National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of TechnoloryHarbin 150001China China FA W Casting Company Limited Changchun 130011China State Key Laboratory of Advanced Welding and JoiningHarbin Institute of Technolory.Harbin 150001.China

To investigate the effect of solidification parameters on the solidification path and microstructure evolution of Ti-45Al-5Nb(at.%) alloy, Bridgman-type directional solidification and thermodynamics calculations were performed on the alloy. The microstructures, micro-segregation and solidification path were *** results show that the β phase is the primary phase of the alloy at growth rates of 5-20 μm·s^(-1) under the temperature gradients of 15-20 K·mm^(-1), and the primary phase is transformed into an α phase at relatively higher growth rates(V >20 μm·s^(-1)). The mainly S-segregation and β-segregation can be observed in Ti-45Al-5Nb alloy at a growth rate of 10 μm·s^(-1) under a temperature gradient of 15 K·mm^(-1). The increase of temperature gradient to 20 K·mm^(-1) can eliminate β-segregation, but has no obvious effect on S-segregation. The results also show that 5 at.% Nb addition can expand the β phase region, increase the melting point of the alloy and induce the solidification path to become complicated. The equilibrium solidification path of Ti-45Al-5Nb alloy can be described as L L→β L+β L+β→αα+β_R β→ααα→γα+γα→α_2+γγ_R+(α_2+γ), in which β_R and γ_R mean the residual β and

关键词： TiAl-Nb alloy directional solidification microstructure micro-segregation solidification path

Dependency of microstructure and microhardness on withdrawal rate of Ti-43Al-2Cr-2Nb alloy prepared by electromagnetic cold crucible directional solidification

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China Foundry 2016年第4期13卷 289-293页

作者： Yong-zhe Wang Hong-sheng Ding Rui-run Chen jing-jie guo Heng-zhi Fu National Key Laboratory for Precision Hot Processing of Metals School of Materials Science and EngineeringHarbin Institute of Technology

The intermetallic Ti-43Al-2Cr-2Nb(at.%)alloy was directionally solidified in an electromagnetic cold crucible with different withdrawal rates(V)ranging from 0.2 to 1.0 mm·min^(-1),at a constant temperature gradients(G=18 K·mm^(-1)).Macrostructures of the alloy were observed by optical *** of the alloy were characterized by scanning electron microscopy(SEM)in back-scattered electron mode and transmission electron *** showed that morphologies of macrostructure depend greatly on the applied withdrawal *** columnar grains can be obtained under slow withdrawal rates ranging from 0.2 to 0.6 mm·min^(-1).The microstructure of the alloy was composed ofα_(2)/γlamellar structures and a small number of mixtures of B2 phases and blockyγ*** columnar grain size(d)and interlamellar spacing(λ)decrease with an increasing withdrawal *** effect of withdrawal rate on microhardness was also *** microhardness of the directional y solidified Ti-43Al-2Cr-2Nb alloy increases with an increase in withdrawal *** is mainly attributed to the increase of B2 andα_(2) phases as well as the refinement of lamellae.

关键词： TiAl-based alloys directional solidification microstructure microhardness

Microstructures and properties of Nb-Si-based alloys with B addition

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Rare Metals 2023年第8期42卷 2801-2808页

作者： Liang-Shun Luo Fu-Xin Wang Xian-Yu Meng Yan-Jin Xu Liang Wang Yan-Qing Su jing-jie guo Heng-Zhi Fu School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China AVIC Manufacturing Technology Institute Beijing 100024China

The Nb-16Si-18Ti-xB(at%,similarly hereinafter,x=0,1,2,3)alloys were prepared by arc melting in a water-cooled copper *** influences of B addition on their microstructures and properties were based on the data of X-ray diffraction(XRD),field emission scanning electron microscopy(FESEM),and electronic universal material testing *** is found that the addition of B promotes the formation ofα-Nb5Si3phase and suppresses the formation of Nb3Si phase.B addition also tends Nb-16Si-18Ti alloy to form the hypereutectic *** content of silicide phases shows a trend of firstly decreasing and then increasing in Nb-16Si-18Ti-xB(x=0,1,2,3)*** size of Nb solid solution(Nbss)phase increases in Nb-16Si-18Ti-xB(x=0,1,2,3)alloys after heat treatment at 1523 K for 10 *** room temperature compression strength of Nb-16Si-18Ti alloy increases firstly and then decreases with B *** high-temperature compression strength of Nb-16Si-18Ti alloy decreases firstly and then increases with B *** is found that the volume and size of silicide phases have a synergistic effect on the compression strength of Nb-TiSi-based alloys.

关键词： Nb-Si alloys B element Phase stability Compression yield strength

Effect of boron on microstructure and mechanical properties of cast Ti-44Al6-Nb ingots

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China Foundry 2015年第1期12卷 9-14页

作者： Jian-chong Li Rui-run Chen Zhi-kun Ma Xiao-yu Chen Hong-sheng Ding jing-jie guo AVIC Beijing Institute of Aeronautical Materials School of Materials Science and Engineering Harbin Institute of Technology Department of Tank Repair People's Liberation Army Armored Force Engineering Institute

In order to improve the mechanical properties of Ti Al alloys, especially the ductility at room temperature, and to study the effect of boron(B) on Ti Al alloys, different contents(0, 0.1, 0.3, 0.6, 0.9, 1.2, at.%) of B were added into Ti-44Al-6Nb alloys to prepare ingots. The surface quality, macrostructure, microstructure, compressive properties and fracture surface of the ingots were studied. The results show that B has little influence on the surface quality except that there are some dark spots on the surface when the content of B is 0.9%. B can refine the grains. The average grain size decrease from about 0.8 mm to 0.088 mm with increasing B content. Meanwhile, the grain morphology of these ingots changes from big equiaxed grains with lamellars to fine equiaxed grains. When the content of B is 1.2%, the primary Ti B2 phase forms in the liquid phase and increases the nucleation rate, leading to further refinement of the grains. The compressive testing results show that B can increase the strength and the ductility, the compressive strength and compressibility can reach 2,037.8 MPa and 26.7% from 1,156.2 MPa and 10.2% when the boron content is 0.6%, which is resulted from grain refining and grain boundary strengthening. It is found that the compressive strength and the compressibility are relatively stable when the B content is more than 0.3%.

关键词： boron TiAl alloy compressive property grain refining

A high-Nb TiAl alloy with highly refined microstructure and excellent mechanical properties fabricated by electromagnetic continuous casting

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China Foundry 2016年第5期13卷 342-345页

作者： Yong-zhe Wang Hong-sheng Ding Rui-run Chen jing-jie guo Heng-zhi Fu Jin-peng Lu National Key Laboratory for Precision Hot Processing of Metals School of Materials Science and Engineering Harbin Institute of Technology Harbin 150001 China

In the present research, microstructure refinement of a high-Nb TiAl alloy （Ti-48Al-8Nb-0.15B） was realized by means of the electromagnetic continuous casting （EMCC） technique. The microstructure of an ingot obtained by EMCC was analyzed using scanning electron microscopy （SEM）. As compared with the raw as-cast alloy, the obtained EMCC alloy presented a much finer microstructure with lamellar colonies with a mean size of about 50-70 μm because the electromagnetic stirring broke initial dendrites and enhanced the heterogeneous nucleation. As the grains were refined, the properties of the TiAl alloy were improved significantly. This implies that the EMCC technique could offer the possibility of application for high-Nb TiAl alloys with a refined microstructure and excellent properties to be used as a structural material.

关键词： high-Nb TiAl alloy microstructure electromagnetic continuous casting mechanical properties

Influence of laser parameters on segregation of Nb during selective laser melting of Inconel 718

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China Foundry 2021年第4期18卷 379-388页

作者： Liang Wang Ran Cui Bin-qiang Li Xue Jia Long-hui Yao Yan-qing Su jing-jie guo Tong Liu School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of TechnologyHarbin 150001China HIT-Chungu Joint Research Center for Additive Manufacturing Materials Anhui Chungu 3D Printing Institute of Intelligent Equipment and Industrial TechnologyWuhu 241200AnhuiChina

A transient three-dimensional powder-scale model was established for understanding the flow field and mass transfer within the molten pool during the selective laser melting(SLM)of Inconel 718 alloy by considering some important physical phenomena,such as,a transition from powder to solid,nonlinearities produced by temperature-dependent materials’properties,and fluid flow in the *** influence of laser power or scanning speed on the flow field and cooling rate was discussed in *** simulation results reveal that the motion of molten pool and higher cooling rate promote the mass transfer and benefit the solute distribution by increasing laser ***,with increasing the scanning speed,the melt flow speed and cooling rate are elevated,resulting in an agglomeration of the solute elements,which is ascribed to the shorter dwelling time of ***,the segregation of Nb can be effectively suppressed by increasing laser power or decreasing scanning speed,which can decrease the dwelling time of liquid.

关键词： selective laser melting Inconel 718 alloy flow field mass transfer segregation