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Influence of hot-rolling on the microstructure and mechanical properties of a near β-type Ti-5.2Mo-4.8Al-2.5Zr-1.7Cr alloy

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Progress in Natural Science:Materials International 2022年第4期32卷 504-509页

作者： Xinjie Zhu qunbo fan Guxin Zhou Duoduo Wang Chinese Weapons Science Academy Ningbo Branch National Key Laboratory of Science and Technology on Materials Under Shock and Impact School of Materials Science and Engineering Beijing Institute of Technology

In this work, the 90° clock rolling and the uni-directionally rolling processes at high temperature were carried out on the near β-type Ti-5.2Mo-4.8Al-2.5Zr-1.7Cr titanium alloy cutting from an ingot, respectively. The corresponding microstructures were quantitatively characterized, and its effect on the dynamic mechanical properties and fracture mechanism were emphatically investigated. It was found that after 90° clock rolling, the microstructure composed of equiaxed primary α phase(αp) with an average size of about 2 μm and the β transformed regions containing the acicular secondary α phase(αs) with an average thickness of about 50 nm and the separated β phase was obtained. However, in the uni-directionally rolled titanium alloy, no acicular αswas observed, and the corresponding microstructure consisted elongated lamellar α phase(average thickness: about 1.3 μm), few equiaxed α phase(average grain size: about 300 nm) and the inlaid β phase. The microstructural difference of the hot-rolled titanium alloys was closely related to the deformation process. Moreover, a great number of αpand αsin the 90° clock rolled titanium alloy effectively enhanced the strength, and the dynamic compressive strength reached to 1730 MPa. Furthermore, equiaxed αpwas conducive to the homogeneous deformation, which counteracted the localized deformation caused by acicular αsto a certain extent and made the 90°clock rolled titanium alloy exhibit an acceptable critical fracture strain of about 10.5%. Moreover, the fracture microstructures showed that the main failure mode of the 90°clock rolled and the uni-directionally rolled titanium alloy were ductile fracture and brittle fracture, respectively.

关键词： 90° clock rolling Microstructure Mechanical properties Titanium alloy

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第一性原理研究钛合金中的沉淀强化

金属学报 2024年第4期60卷 537-547页

作者：程坤陈树明曹烁刘建荣马英杰范群波程兴旺杨锐胡青苗中国科学院金属研究所师昌绪先进材料创新中心沈阳110016 中国科学技术大学材料科学与工程学院沈阳110016 北京理工大学材料学院冲击环境材料技术重点实验室北京100081

为研究合金化对沉淀强化行为的影响,采用第一性原理方法计算了二元Ti-xM(M=Al、V、Cr、Mn、Fe、Co、Ni、Zr、Nb、Mo、Ta、W)合金弹性模量随成分的变化,提出了弹性模量Mo当量概念,以高效计算复杂成分钛合金(如Ti-Al-V合金以及Ti55521)的... 详细信息

为研究合金化对沉淀强化行为的影响,采用第一性原理方法计算了二元Ti-xM(M=Al、V、Cr、Mn、Fe、Co、Ni、Zr、Nb、Mo、Ta、W)合金弹性模量随成分的变化,提出了弹性模量Mo当量概念,以高效计算复杂成分钛合金(如Ti-Al-V合金以及Ti55521)的弹性模量;结合弹性模量及Russell-Brown沉淀强化模型,研究了二元Ti-xM(M=V、Cr、Mn、Fe、Co、Ni、Nb、Mo、Ta、W)合金以及Ti55521合金中的沉淀强化。结果显示,在体积分数及沉淀相颗粒尺寸相同的情况下,Co、Fe、W、Mo、Ni、Mn沉淀强化作用较强,Cr、Nb、Ta强化作用居中,V强化作用最弱。随合金元素含量x增加,沉淀强化作用均有所增强。热机械处理Ti55521合金经短时时效后,沉淀强化作用有所减弱,但长时时效后,沉淀强化效果增强。

关键词：第一性原理钛合金弹性模量沉淀强化强度

Composition design of a novel Ti-6Mo-3.5Cr-1Zr alloy with high-strength and ultrahigh-ductility

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Journal of Materials Science & Technology 2022年第36期131卷 276-286页

作者： Kai Chen qunbo fan Jiahao Yao Lin Yang Shun Xu Wei Lei Duoduo Wang Jingjiu Yuan Haichao Gong Xingwang Cheng National Key Laboratory of Science and Technology on Materials Under Shock and Impact School of Materials Science and EngineeringBeijing Institute of TechnologyBeijing 100081China Beijing Institute of Technology Chongqing Innovation Center Chongqing 401135China

The strength-elongation to fracture(εf)trade-off and low strain hardening rate have been a longstanding dilemma in titanium *** this work,we innovatively manufactured a novel Ti-6Mo-3.5Cr-1Zr alloy via the introduction of a stress-induced strengthening phase into the ***-inducedω(SIω)phase transformation was expected to replace theα''martensitic transformation that resulted in the low yield strength of titanium *** obtained alloy exhibited an extremely high strain hardening rate of up to^1820 *** true peak tensile strength andεfreached^1242 MPa and^40%,*** intrinsic mechanisms underlying the simultaneous improvement of strength and ductility of the material were systematically investigated via in-situ and ex-situ ***-situ electron backscatter diffraction(EBSD)/digital image correlation(DIC)results showed that SIωphase transformation dominated the early stage of plastic deformation(1.5%–3%)and promoted the strain partitioning between the stress-induced bands andβ***,the formation of{332}βtwins andωtwins was observed via ex-situ ***-situ transmission electron microscopy results revealed that dislocation pile-up(DPU)occurred at the SIω/β*** coupling effects associated with the transformation induced plasticity(TRIP),twinning induced plasticity(TWIP),and DPU mechanisms contributed to the enhanced strength andεfof the designed titanium alloy.

关键词： Titanium alloy Mechanical properties Phase transformation Twinning Strain partitioning

Texture evolution and slip mode of a Ti-5.5Mo-7.2Al-4.5Zr-2.6Sn-2.1Cr dual-phase alloy during cold rolling based on multiscale crystal plasticity finite element model

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Journal of Materials Science & Technology 2022年第16期111卷 76-87页

作者： Duoduo Wang qunbo fan Xingwang Cheng Yu Zhou Ran Shi Yan Qian Le Wang Xinjie Zhu Haichao Gong Kai Chen Jingjiu Yuan Liu Yang National Key Laboratory of Science and Technology on Materials Under Shock and Impact School of Materials Science and EngineeringBeijing Institute of TechnologyBeijing 100081China Beijing Institute of Technology Chongqing Innovation Center Chongqing 401135China Microstructure and Properties of Materials(IEK-2) Forschungszentrum JülichJülichGermany Chengdu Advanced Metal Materials Industrial Technology Research Institute Co.Ltd Chengdu 610000China

The complex micromechanical response among grains remains a persistent challenge to understand the deformation mechanism of titanium alloys during cold ***,in this work,a multiscale crystal plasticity finite element method of dual-phase alloy was proposed and secondarily developed based on LS-DYNA ***,the texture evolution and slip mode of a Ti-5.5Mo-7.2Al-4.5Zr-2.6Sn-2.1Cr alloy,based on the realistic 3D microstructure,during cold rolling(20%thickness reduction)were systematically *** relative activity of the■slip system in theαphase gradually increased,and then served as the main slip mode at lower Schmid factor({110}slip system showed an upward tendency,indicating the important role of the critical resolved shear stress relationship in the relative activity ***,the abnormally high strain of very fewβgrains was found,which was attributed to their severe rotations compelled by the neighboring pre-deformedα*** calculated pole figures,rotation axes,and compelled rotation behavior exhibited good agreement to the experimental results.

关键词： Titanium alloy Multiscale crystal plasticity finite element model Texture evolution Slip mode

Microstructure evolution and mechanical properties of a hot-rolled Ti alloy

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Progress in Natural Science:Materials International 2021年第1期31卷 105-112页

作者： Xinjie Zhu qunbo fan Xin Liu Hong Yu Duoduo Wang School of Materials Science and Engineering Beijing Institute of Technology National Key Laboratory of Science and Technology on Materials Under Shock and Impact Beijing Institute of Technology Beijing Institute of Technology Chongqing Innovation Center

The microstructure evolution and mechanical properties of a hot-rolled Ti-5.1 Al-2.5 Cr-0.5 Fe-4.5 Mo-1.1 Sn-1.8 Zr-2.9 Zn titanium alloy sheet along the thickness direction were *** results indicated that the hotrolled titanium alloy sheet presented different microstructures along the thickness direction owing to the uneven distribution of stress and temperature during the hot *** grains in central region underwent a larger deformation,leading to relative complete grain fragmentation and the formation of fine *** the air cooling process followed by hot rolling,the fraction of a phase precipitated in the central region was lower than that in the regions near the surface of the *** hot rolling process,more deformation energy transformed to thermal energy and lower cooling rate in the central region promoted the α→β phase transformation,resulting in the increasing of the dynamic recrystallization in the β *** contrast,the dynamic recrystallization for a phase *** {0001}αand {001}βtextures were observed,and these textures were markedly strengthened with the increasing distance from the central *** to the softening induced by dynamic recrystallization and the strengthening by concentrated dislocations,the surface of the sheet exhibits highest yield strength and lowest elongation.

关键词： Titanium alloys Microstructure evolution Mechanical properties Hot rolling

Multi-scale crystal plasticity finite element simulations of the microstructural evolution and formation mechanism of adiabatic shear bands in dual-phase Ti20C alloy under complex dynamic loading

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Journal of Materials Science & Technology 2020年第24期59卷 138-148页

作者： Yu Zhou qunbo fan Xin Liu Duoduo Wang Xinjie Zhu Kai Chen School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China National Key Laboratory of Science and Technology on Materials Under Shock and Impact Beijing 100081China Beijing Institute of Technology Chongqing Innovation Center Chongqing 401135China

A dynamic compression test was performed on α+β dual-phase titanium alloy Ti20C using a split Hopkinson pressure *** formation of adiabatic shear bands generated during the compression process was studied by combining the proposed multi-scale crystal plasticity finite element method with experimental *** complex local micro region load was progressively extracted from the simulation results of a macro model and applied to an established three-dimensional multi-grain microstructure ***,the evolution histories of the grain shape,size,and orientation inside the adiabatic shear band were quantitatively *** results corresponded closely to the experimental results obtained via transmission electron microscopy and precession electron ***,by calculating the grain rotation and temperature rise inside the adiabatic shear band,the microstructural softening and thermal softening effects of typical heavily-deformed α grains were successfully *** results revealed that the microstructural softening stress was triggered and then stabilized(in general)at a relatively high *** indicated that the mechanical strength was lowered mainly by the grain orientation evolution or dynamic recrystallization occurring during early plastic ***,thermal softening increased linearly and became the main softening ***,in the final stage,the thermal softening stress accounted for 78.4% of the total softening stress due to the sharp temperature increase,which inevitably leads to the stress collapse and potential failure of the alloy.

关键词： Titanium alloy Adiabatic shear band Multi-scale crystal plastic finite element method(CPFEM) Orientation evolution Softening mechanism

Optimization Methodology of Empirical Electronic Theory by Employing Statistical Model

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Journal of Beijing Institute of Technology 2018年第3期27卷 426-432页

作者： Donghu Yang qunbo fan Fuchi Wang Lu Wang Tiejian Su School of Material Science and Engineering Beijing Institute of Technology

An optimization methodology of empirical electronic theory(EET)for solids and molecules has been developed by employing a statistical model in this *** current paper calculates the hybridization states of different atoms in some crystal structures and succeeds in predicting valence states of *** prediction ofγ-Fe hybridization states based on statistics is found to be in reasonable agreement with early *** calculating Cr alloy austenite and Cr alloy martensite,the statistical results proved stable for each atom,and it is found that the valence electron structure of an atom depends on its element type and location in the crystal cell;finally,wear resistant steel with1 wt% C is designed by using a statistical model which is consistent with traditional empirical design.

关键词： empirical electronic theory(EET) statistical model valence electron structure(VES) ma-terial design

Damage Characteristic of Interpenetrating Phase Composites under Dynamic Loading

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Journal of Wuhan University of Technology(Materials Science) 2014年第4期29卷 698-703页

作者：王富耻 ZHANG Xu 王扬卫 WANG Lu MA Zhuang fan qunbo School of Materials Science and Engineering Beijing Institute of Technology National Key Laboratory of Science and Technology on Materials under Shock and Impact

In order to investigate the damage characteristic of ceramic-metal interpenetrating phase composite（IPC） under dynamic loading, uniaxial dynamic compression was performed to characterize the failure of SiC/Al composite with 15% porosity using a modifi ed Split Hopkinson Pressure Bar（SHPB）. High speed photography was used to capture the failure procedure and set up the relationship between deformation and real stress. The deformation control technology was used to obtain collected samples in different deformations under dynamic loading. Micro CT technology was utilized to acquire real damage distribution of these specimens. Moreover, SEM was employed in comparing the damage characteristics in IPC. A summary of the available experimental results showed that IPC without lateral confi nement formed double cones. The different features compared with ceramic materials without restraint was shown to be the result of the lateral restraint effect provided by metal phase to ceramics skeleton.

关键词： interpenetrating phase composites damage characteristic double cones

Zr_(77.1)Cu_(13)Ni_(9.9)非晶合金破片侵彻LY12铝合金及TC4钛合金靶板毁伤后效及机理对比研究

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北京理工大学学报 2023年第4期43卷 417-428页

作者：杨林于述贤范群波北京理工大学材料学院北京100081 北京理工大学冲击环境材料技术国家级重点实验室北京100081

锆基非晶合金是极具发展潜力的含能结构材料,由其制备的破片侵彻不同材质装甲时,会表现出显著不同的毁伤效果.本研究中利用弹道枪发射装置,针对Zr_(77.1)Cu_(13)Ni_(9.9)非晶合金破片,以1200 m/s速度分别侵彻8 mm厚LY12铝合金和TC4钛合... 详细信息

锆基非晶合金是极具发展潜力的含能结构材料,由其制备的破片侵彻不同材质装甲时,会表现出显著不同的毁伤效果.本研究中利用弹道枪发射装置,针对Zr_(77.1)Cu_(13)Ni_(9.9)非晶合金破片,以1200 m/s速度分别侵彻8 mm厚LY12铝合金和TC4钛合金屏蔽靶,结合高速摄影技术比较了破片碎裂形成碎片云并造成毁伤后效的过程;同时基于FEM/SPH自适应耦合法,再现了破片对两类屏蔽靶开坑、稳定侵彻、穿透等系列阶段,以及碎片云形成的复杂物理过程,揭示了其对后效靶的毁伤机理.结果表明,由于TC4钛合金相比LY12铝合金具有更高的强度,穿透TC4屏蔽靶所需的时间更长,且靶板内最大等效应力是后者的3倍左右;破片在侵彻TC4屏蔽靶时与靶板间发生了更强的相互作用,使得破片前端出现更大面积的高应变区域,由此导致破片发生了更严重的破碎并产生分布范围更大的碎片云,从而在后效靶上产生更大面积的损伤.

关键词： Zr基非晶合金结构释能破片 FEM/SPH耦合方法数值模拟毁伤后效