2015 Atom Probe Tomography Forum

(Abstract)Oct.29-Oct.30,Nanjing,China

Chinese Centre of Excellence For Atom Probe

Tomography

Chemical Imaging of Interfaces and Interphases

in Tooth Biominerals

Derk JoesterMaterials Science and Engineering

Northwestern Universityd-joester@northwestern.edu

Abstract:Tooth biominerals are among the hardest biological materials.

Optimized to withstand the forces of mastication, they are hierarchically structured,

organic/inorganic nanocomposite materials. For example, the radular teeth of the chiton

are capped with a composite made from magnetite (Fe3O4) and a nanofibrous chitin

scaffold. These teeth are sufficiently hard that the chiton can abrade rocks during feeding.

Human tooth enamel is composed of hydroxylapatite nanowires, thousands of which are

bundled into rods that are organized in a three-dimensional weave; this provides great

fracture resistance and a much enhanced fatigue life. It has long been known that the

susceptibility of enamel to caries, i.e. acid corrosion, is greatly dependent on the presence

of magnesium, carbonate, and fluoride ions. However, imaging the distribution of these

impurities and organic/inorganic interfaces in the teeth has remained challenging.

I will discuss how UV-laser pulsed atom probe tomography (APT), in combination

with correlative imaging and spectroscopy techniques, has given us new insights into the

chemistry of organic/inorganic interfaces and grain boundaries.1-5 In particular, we

discovered that the presence of Mg-substituted amorphous calcium phosphate (Mg-ACP)

as an interphase has a dramatic influence on the susceptibility of enamel to acid corrosion.

Inspiration how to overcome this weakness comes from pigmented rodent enamel. Here,

an intergranular amorphous phase of metastable ferrihydrite and amorphous calcium/iron

phosphate replaces the much more soluble Mg-ACP in regular enamel. This substitution

not only renders pigmented enamel mechanically harder, but also hardens it to acid attack

to a greater extent than topical fluoride treatment. This discovery will pave the way for

bio-inspired engineering of enamel grain boundaries and for developing next generation,

“post fluoride” dental care products.

Figure 1. Atom probe tomography reconstructions of A: regular mouse enamel; B: pigmented ratenamel; C: multiple grain boundary in mouse enamel; D: amorphous interphase in pigmented rat enamel.

[1] Gordon, L. M., Joester, D., Nature 2011, 469, 194-197. "Nanoscale chemical tomography ofburied organic-inorganic interfaces in the chiton tooth."

[2] Gordon, L. M., Tran, L., Joester, D., ACS nano 2012, 6, 10667-10675. "Atom probe tomographyof apatites and bone-type mineralized tissues."

[3] Gordon, L. M., Román, J. K., Everly, R. M., Cohen, M. J., Wilker, J. J., Joester, D., Angew Chem

Int Ed 2014, 53. "Selective formation of metastable ferrihydrite in the chiton tooth."[4] Gordon, L. M., Cohen, M. J., MacRenaris, K. W., Pasteris, J. D., Seda, T., Joester, D., Science

2015, 347, 746-750. "Amorphous intergranular phases control the properties of rodent toothenamel."

[5] Gordon, L. M., Joester, D., Frontiers in Physiology 2015, 6. "Mapping residual organics andcarbonate at grain boundaries and in the amorphous interphase in mouse incisor enamel."

——————————————————————————————————

Study on the precipitation behavior of dispersoids

containing Mn and Cr in Al-Mg-Si-Cu alloy

报告人介绍：长海博文，苏州有色金属研究院有限公司副总经理，国家“千人计划”

专家，江苏省高层次引进人才，教授。

Abstract:The precipitation behavior of dispersoids containing Mn and Cr in

Al-Mg-Si-Cu alloy during homogenization annealing was investigated in this paper.

Scanning transmission electron microscopy (STEM) was used to study the size and

crystal structure of dispersoids in the alloy. It demonstrates that the density and size of

dispersoids were greatly dependent on the heating rate in homogenization. EDS mapping

analysis shows the two types of precipitates, i.e. platelets and little blocks, after

homogenization. Cu did not participate in high temperature precipitation and distributed

uniformly inside the matrix. The precipitation sequence of the main elements in the

precipitates was revealed using 3D atom-probe tomography. It was found that Q-phase

was the precursor phase for the formation of dispersoids. Mn atoms first segregated

themselves at the interface between lathe-shaped Q-phase and the matrix in the early

stage of the precipitation process. After Mn cluster formation, Si atoms subsequently

participated in the process of dispersoids formation. The atomic ratio of Mn/Si in

dispersoids was close to 1.

——————————————————————————————————

Structure, Magnetic and Mechanical Properties

of Fe-based Bulk Metallic Glasses

Baolong Shen

School of Materials Sciences and Engineering, Southeast University, Nanjing, China

Email:blshen@seu.edu.cn,

Abstract:Fe-based bulk metallic glasses (BMGs) have attracted great attention

ever since their first synthesis in 1995 due to their unique magnetic and mechanical

properties. In this talk, I will report a series of novel Fe-based BMGs, such as

FeREBNb (RE=Dy, Gd, Tb, Ho, Er, Tm) and FeNiPC alloys. These Fe-based BMGs

exhibit good soft magnetic properties, large magnetostriction, large magnetic entropy

change, high strength and unprecedented compressive plasticity at room temperature,

which have not been obtained in conventional Fe-based crystalline alloys. This

uniqueness has led to practical uses of these bulk glassy alloys as soft magnetic and

structural materials. Meanwhile, the mechanism of ductile-to-brittle transition for

Fe-based BMGs were also investigated. It was discovered that the ductile Fe-based

BMG is composed of unique clusters mainly linked by less directional metal-metal

bonds which are inclined to accommodate shear strain and absorbed energy in the

front of crack tip. This conclusion was further verified by the X-ray photoelectron

spectroscopy and ultraviolet photoelectron spectroscopy experiments of brittle to

ductile Fe-based glassy systems. The results also indicate a strong correlation between

the p-d hybridization and plasticity, verifying that the transition from brittle to ductile

is due to the change of bonding characteristics in atomic configurations.

——————————————————————————————————

laser melting and the applications of APT technology in

mechanism analysis

Wei Liu, Xin Zhou

School of Materials Science and Engineering, Tsinghua University, 100084, Beijing,China

Abstract:The unique sub-grain microstructures found in some alloys (316L,

Al-Si, Co-Cr-Mo) selective laser melting (SLM) is still a confusing question which

cannot easily explained by constitutional supercooling theory, because the

submicron-scale cellular, elongated cellular, and even bands structures are always

coexisted inside in one single macro-solidified-grain. There has a speculation that the

complex cellular sub-grain patterns are formed by local convection and Bénard

Instabilities in front of the solid/liquid (S/L) interface (so-called mushy zones) under

complex temperature and surface tension gradients.

To confirm the validity of this speculation, APT technology is an urgent analysis

method. The microsegregations and distinct element distributions can be explained by

particle accumulation structures (PAS) mechanism, this is the behavior of small

particles of dilute concentration in time-dependent (oscillatory) ring vortex

thermocapillary flow, APT technology is a powerful tool in conducting in-depth

research.

Key words: Selective laser melting; Thermocapillary convection;Bénard-Marangoni-instability; Sub-grain structures; Atom Probe Tomography(APT)

——————————————————————————————————

A Low Density Steel for Bearings

报告人介绍：易红亮，1981年 1月生，博士，轧制技术及连轧自动化国家重点实验室（东北大学）教授。2002年 7月本科毕业于哈尔滨工业大学材料成型及控制系，2005年 7月硕士毕业于哈尔滨工业大学材料学系，2010年 8月博士毕业于韩国浦项工科大学钢铁物理冶金专业 H. K. D. H. Bhadeshia教授计算金属学实验室。2005年 7月至 2006

javascript:void(0);

年 12月于中国汽车工程研究院材料与工艺研究部负责钢铁材料汽车应用研究，2010 年8 月至 2012 年 12 月于莱芜钢铁集团技术中心任首席研究员/副所长。目前主要学术研究

方向为先进钢铁材料设计及钢铁材料焊接冶金，具体包括汽车用先进高强度钢（δ-TRIP钢、中Mn-TRIP钢、新一代高强高延性热冲压成形用钢、低密度高弹性模量钢）、新型低密度轴承钢、汽车用钢电阻点焊等。目前正负责自然科学基金青年基金 1项，钢铁

联合基金重点项目 1项；负责 POSCO 合作项目 2项，鞍钢、本钢合作项目各 1项。近 5

年发表 SCI 论文（第一作者/通信作者）15 篇，H因子 8。

摘要：轴承钢因其高耐疲劳性能以及高耐磨性的使用需求，要求其具有高硬度以及

高强度。52100轴承钢已应用了上百年，其通过临界区奥氏体化温度淬火之后获得马氏体，3wt.%~4wt.%的未溶解的碳化物以及~6vol.%的残余奥氏体，回火之后来满足轴承的使用要求。但 52100轴承钢存在几方面的缺点降低其使用性能，其中包括：1）严重过共析碳含量形成的网状碳化物影响组织的均匀性；2）较高的碳含量降低马氏体相变温度点，降低马氏体量，即使碳含量增加也不能提高轴承钢的硬度；3）为保证轴承的尺寸稳定性，轴承钢会通过回火消除残余奥氏体，回火残余奥氏体的含量少于 3vol.%，所以轴承钢的韧性以及抗氢脆能力较差。新设计的轴承钢“1.2C-1.5Cr-5Al”在提高硬度、强度的同时，弥补了 52100轴承钢的不足。“1.2C-1.5Cr-5Al”轴承钢：5wt.%Al的加入 1）将轴承钢的密度降低 8%；2）将共析碳含量右移到 1.2wt.%，因此该低密度轴承钢为共析设计，消除网状碳化物；3）提高马氏体相变温度点，增加马氏体体积分数，所以碳含量的增加与 Al的复合添加使轴承钢在经过淬火、冷处理以及回火之后轴承钢的硬度值达到 64±0.2HRC，压缩强度值为 3.22±0.02Gpa。高碳轴承钢的残余奥氏体可改善其韧性，同时提高其抗氢脆能力，但残余奥氏体会在轴承服役过程中因 TRIP效应而导致轴承尺寸变化，因此传统轴承钢中须通过马氏体回火热处理尽可能降低残余奥氏体分数。本研

究提出新的设计，通过回火工艺实现低温贝氏体相变，在新的合金体系下，可实现超高

碳（4.6wt.%）纳米尺寸薄膜残余奥氏体，亦使该奥氏体具有超高稳定性，在大的应力下不发生 TRIP效应保证其尺寸稳定性。将经过淬火以及冷处理的轴承钢在 200oC保温144h进行贝氏体相变，将贝氏体中过饱和的碳配分进入奥氏体中提高奥氏体的稳定性，同时因 Al将 T0曲线右移提高残余奥氏体中的碳含量。3D原子探针测的薄膜残余奥氏体中的碳含量达到 4.3~4.91wt.%，与理论预测值 4.6wt.%一致。低温贝氏体相变获得奥氏体的薄膜厚度经透射电镜观察为 10~50nm，贝茵铁素体薄膜厚度为 20~80nm。因此该残余奥氏体可具有超高稳定性。实验证明了该残余奥氏体在压缩变形过程中未发生 TRIP效应。

——————————————————————————————————

3D Atom-by-Atom Analysis of Solid Solution Architecture

R.K.W. Marceau

r.marceau@deakin.edu.au

Deakin University, Institute for Frontier Materials, Geelong, VIC 3216, Australia

Abstract:The challenge in characterising atomistic-level structures is that it pushes

the limits of resolution and detection of most microscopy and characterisation techniques.

Atom probe tomography (APT) provides a unique combination of highly resolved

chemical and spatial information in three dimensions (3D) and so far, this technique is the

closest to achieving the ultimate in microscopy, i.e. to accurately locate and identify every

atom in the specimen and provide capacity to reveal both composition and

crystallographic structure at the atomic scale. As such, compared to other techniques, APT

is particularly suited to characterising the chemical architecture of a solid solution, which

is recognised as a key factor in engineering the formation and evolution of nanostructure

within metallic alloys that influences material properties.

In this talk, I will focus on the atomic-scale characterisation circumstances where

APT has made a unique contribution to materials science due to atom-by-atom analysis

afforded by the 3D data: namely, the investigation of solute clustering and short-range

order (SRO). With respect to the former, recent work on the analysis of

cluster-strengthening of the automotive 6111 aluminium alloy will be highlighted, in

addition to a review of cluster-finding analysis developments and future directions.

Quantitative analysis of SRO using APT data is outlined by introduction of the

generalised multicomponent (GM-)SRO parameters, which are calculated by shell-based

analysis of the 3D atomic positions to determine chemically sensitive SRO information.

An intermetallic Fe-18Al (at.%) alloy is used as a case study in an attempt to understand

the nature of the so-called ‘komplex’ phase state (or “K-state”), which is common to other

alloy systems having compositions at the boundaries of known order-disorder transitions.

The accuracy of the APT-based GM-SRO method with respect to limited detector

efficiency and spatial resolution is tested against modelled D03 ordered data.

——————————————————————————————————

Segregation induced hardening by annealing

and inverse Hall-Petch relationship in

nanocrystalline elements and alloys?

报告人介绍：沈同德教授，男，1965 年 4 月出生，1995 年于中科院金属所获得博

士学位，燕山大学亚稳材料制备技术与科学国家重点实验室教授、博士生导师， 国家

“千人计划”特聘专家。主要研究纳米与非晶材料的制备、结构、磁性、力学、电化学、

辐照损伤行为。曾任美国洛斯阿拉莫斯国家实验室终身研究员, 入选 2009 年度“江苏

省高层次创新创业人才引进计划”。 担任全国非晶材料学术委员会理事、 中国材料研

究学会纳米材料与器件分会理事。在国际学术会议上作特邀和口头报告 33 次,并 6次担

任国际学术会议的分会主席。 在 Nature Materials、 Nano Letters、 PNAS、 Acta

Materialia、Physical Review B、 Applied Physics Letters 等国际著名学术刊物发

表学术论文 100 余篇，SCI 引用约 2500 余次。申请中美发明专利 10 项。

Abstract:We have found a hardening effect in annealed iron- and nickel-based

nanocrystalline alloys and a softening effect in annealed pure (99.9+%) nanocrystalline

iron. As a result, abnormal Hall-Petch relations were observed in annealed nanocrystalline

alloys rather than in annealed pure nancrystalline iron. The hardening effect and the

corresponding abnormal Hall-Petch relations are ascribed to the segregation of solutes

and/or impurities in the grain boundary because of three evidence: i) hardening by

annealing has been observed in many annealed nanocrystalline alloys and low-purity (<

99%) nanocrystalline metallic elements (Al, Ti, Fe), but not in annealed high-purity (>

99.9%) nanocrystalline metallic elements (Al, Ni, Fe); ii) annealing embrittlement occurs

in nanocrystalline alloys; and iii) decreasing the cooling rate used to cool the annealed

nanocrystalline alloys from annealing temperature to room temperature increases the

microhardness. In addition, our experiment results suggest that i) the dislocations –

mainly taking the form of dislocation dipoles – stored in the grain interiors of our

nanocrystalline alloys do not change the microhardness, and ii) it is the grain size and the

grain boundary structure, rather than the dislocations stored in the grain interiors, that

determines the strength of deformed and annealed nanocrystalline elements and alloys.

——————————————————————————————————

原子探针层析技术 (APT) 在超细晶铝合金中

的最新进展及应用

报告人介绍：刘满平，博士，江苏大学教授，科技部国际科技合作及国家自然科学

基金同行评议专家，挪威科技大学访问教授，留学挪威出站博士后，“中挪轻合金及新

能源国际研讨会”第 1–5届组委会执行委员，Mater. Sci. Eng. A、J. Alloys Comp.、J. Mater.

Res.、Mater. Char.和 Intl. J. Mech. Sci.等杂志审稿人，Trans. Nonferrous Met. Soc. China

客座编辑。主要从事大塑性变形铝合金和镁合金纳米结构材料、纳米晶金属材料的研究

与应用，金属材料及成形技术的教学和科研工作。近年来在 Appl. Phys. Lett.、Mater. Sci.

Eng. A、德国《金属学报》(Z. Metallkd.) 和 J. Mater. Sci.等杂志发表论文 80余篇，其中

SCI收录 40余篇，SCI同行专家引用 300余次，H因子达到 12，论文最高影响因子 3.9，

单篇论文最高引用 100多次。参加国际会议 18次，其中组织国际会议 5次，大会或特

邀报告 9次。

摘要：原子探针层析技术 (APT)，可在原子尺度上表征金属材料中的成分和原子空

间位置信息，有望在研究金属材料的微观结构如位错、晶界、析出相、溶质原子扩散和

偏析等方面取得新的重要成果，进而对新材料的设计、开发和应用产生深远影响。本文

在介绍 APT的发展历程、工作原理及数据分析等最新成果的基础上，以 5000系和 6000

系铝合金为对象，综述了 APT在大塑性变形超细晶铝合金中的最新进展及应用。

关键词：原子探针层析技术，表征，大塑性变形，超细晶铝合金

——————————————————————————————————

测试参数对 Inconel 690合金成分分析的影响

报告人介绍：李慧，博士，副研究员，负责上海大学 LEAP 4000X HR 设备日常测试

与维护。

摘要：利用 LEAP 4000X HR 设备对 Inconel 690 合金的成分进行了测定。在同一样

品上分别选取了不同样品温度、不同激光能量进行成分测试，分析样品温度及激光能量

对样品成分的影响。结果表明，在 50 K 用 60 pJ 进行测试时得到的成分与实际成分接

近。

——————————————————————————————————

Effect of deformation temperature on the microstructures and

mechanical properties of high-strength extruded

Mg-Al-Ca-Mn alloy

S. W. Xu *Research Institute (R & D Centre), Baosteel Group Corporation, Shanghai, China

Abstract:In this study, a direct-chill (DC) cast Mg-Al-Ca-Mn alloy was

subjected to indirect extrusion at temperatures ranging from 400 oC to 475 oC under a

low ram speed of 0.1 mm s-1. The influence of deformation temperature on the

microstructure and mechanical properties of extruded Mg-Al-Ca-Mn alloy was

systemically investigated by the electron backscattering diffraction (EBSD) analysis,

the transmission electron microscopy (TEM) and the Laser-assisted 3D atom probe

(3DAP). The sample extruded at 400 oC exhibited a high tensile 0.2% proof stress

( TPS) of 409 MPa, a compressive 0.2% proof stress ( CPS) of 336 MPa and a

tensile elongation to failure of 8.1 %, due to the combined effect of fine dynamically

recrystallized (DRXed) grains pinned with fragmented Mg2Ca and (Mg, Al)2Ca

intermetallic compounds, nano-scale plate-like Al-Ca precipitates in un-DRXed

region, spherical Al-Mn-Ca precipitates, and a strong basal texture. Increasing

deformation temperature leads to a dramatic increase in the volume fraction of

DRXed grain, thus the enhanced ductility and improved yield asymmetry

( CPS/ TPS) were obtained. However, due to the growth of DRXed grain and nano

precipitates with increasing deformation temperature, there is also a decrease in the

proof stress, but the tensile 0.2% proof stress are still higher than 330 MPa.

Keywords: Magnesium alloy; Extrusion; Deformation temperature;Microstructure; Mechanical properties——————————————————————————————————

Application of APT on nanocluster strengthened steels

Zhongwu Zhang

Harbin Engineering University

Abstract:Nanoscale clusters can significantly improve the mechanical properties

of nanoscale precipitate-hardened steels. Tailoring the precipitation process of nanoscale

clusters is essential to understand the strengthening mechanisms and finally, to design

novel alloys. Atom probe tomography (APT) is a state-of-the-art characterization

technique for individual nanoclusters study. In this report, the application of APT on two

kinds of nanocluster strengthened steels will be presented. One is Y-Ti-O-enriched

nanocluster-strengthened steel, which exhibits excellent high temperature properties and

radiation tolerance due to the formation of Y-Ti-O-enriched nanoclusters. The other one is

Cu-enriched nanoscale co-precipitates strengthened steels. By producing nanoscale

co-precipitates in composition-optimized multicomponent precipitation-hardened alloys,

a unique approach to improve the stability of the alloy against thermal aging and hence

the mechanical properties will be demonstrated. This co-precipitate provides a more

complex obstacle for dislocation movement due to atomic ordering together with

interphases, resulting in a high yield strength alloy without sacrificing alloy ductility. The

results of these studies also shed light on the application of APT on the nanocluster

characterization in alloy systems.

——————————————————————————————————

镍基单晶高温合金微观结构的扫描透射电镜研究

葛炳辉 1 郭伟 2 骆宇时 3 朱静 4

中国科学院物理研究所，北京凝聚态物理国家实验室

北京理工大学物理学院

北京航空材料研究院

北京电镜中心，清华大学材料系

摘要：我们利用扫描透射电镜结合 EDS 研究了镍基单晶高温合金的微观结构尤其

是其中的重原子分布，并对其强韧化机理进行了探讨。研究表明在蠕变后的合金中，重

原子 Re 和 W 在在γ 相内靠近界面处富集，并推测在γ 相中的重原子团簇可能均富含

Re 和 W[1]；在合金界面处存在生长台阶，重元素 Re和 W 在台阶的顶点富集[2]；当位

错位于界面附近时，位错附近会发生 Re 和 Mo 元素的富集[1]。最近，通过 HAADF 像分

析发现，重原子在合金中沿[110]方向排列，形成 1-2nm 长的重原子条带，这一发现得

到第一原理计算的验证[3]。上述重原子分布都对合金的强韧化产生积极作用。

[1] B.H. Ge, Y.S. Luo, J.R. Li, J. Zhu, Scripta Mater., 63 (2010) 969-972.[2] B. Ge, Y. Luo, J. Li, J. Zhu, Metall. Mater. Trans. A, 42 (2011) 548-552.[3] Y. Luo. et. al. Submitted.——————————————————————————————————

预变形对自然时效 Al-Cu-Mg合金团簇、力学性能

及加工硬化的影响

报告人介绍：邵迪,西安交通大学金属强度国家重点实验室博士

摘要：我们主要采用电阻率测量、三维原子探针、硬度和拉伸测试来研究预变形对

自然时效 Al-Cu-Mg 合金团簇行为、力学性能及加工硬化的影响。在研究中我们发现预

变形会促进溶质原子团簇的快速形成，但是在长期的时效过程中，预变形对团簇的形成

和长大起到抑制的作用，并且随着预变形的增加，在时效后溶质原子团簇的密度会减小。

综合考虑溶质原子团簇和预变形过程中产生的位错的耦合影响，我们对 Al-Cu-Mg 合金

的屈服强度和加工硬化行为建立了相应的模型。这个模型揭示了在自然时效铝合金中，

溶质原子团簇强化和位错强化是同等重要的。而合金的加工硬化行为并没有因为溶质原

子团簇的形成而发生显著的变化。没有预变形的试样和预变形为 9%的试样的屈服强度和

硬度的比值从 2.1 变化到 3。这主要是由于溶质原子团簇和预变形产生的位错在变形行

为上的竞争机制导致的。

——————————————————————————————————

Precipitation behaviors of advanced Al-Mg-Si-Cu-(Zn) alloys

for automotive applications

Mingxing Guoa, Gang Shab, Jishan Zhanga, Linzhong Zhuangaa State Key Laboratory for Advanced Metals and Materials, University of Science and Technology

Beijing, Beijing, 100083，PR Chinab School of Materials Science and Engineering, Nanjing University of Science and Technology,

Jiangsu 210094, PR China

Abstract: The excellent bake hardening response was achieved in the

Al-Mg-Si-Cu alloys by adding Zn and pre-aging treatment. The precipitation

behaviors and strengthening of natural aged (T4) and pre-aged (T4P) alloys were

investigated by differential scanning calorimetry (DSC), mechanical property

measurement, three-dimensional atom probe (3DAP) analysis and theoretical

modeling. It is shown that, both Zn additiion and pre-aging give a significant effect on

the low temperature precipitation process, GP zone dissolution and β″ precipitation,

which is further verified by the activation energy of GP zone dissolution and β″

precipitation calculated by a modified Avrami-Johnson-Mehl method. The theoretical

models for prediction of GP zone dissolution and precipitation kinetics have been

developed. Additionally, the mechanical properties under different conditions

significantly depend on alloy composition and pre-aging treatment, the highest bake

hardening increment of 135MPa can be achieved in the pre-aged alloy with Zn

addition. A new developed strengthening model can better reveal the separate

contributions of precipitates with different shapes, arrangement and volume fraction

to the mechanical properties. According to the systematic 3DAP maps for the

distribution of solute clusters and precipitates, the different bake hardening response

was systematically analyzed by the developed precipitation kinetics, strengthening

model and microstructure characteristic.

Keywords: Al-Mg-Si-Cu-(Zn) alloy, solute cluster, pre-aging, precipitationbehavior, strengthening——————————————————————————————————

（注：摘要内容以会前发送回执为准）

镍基单晶高温合金微观结构的扫描透射电镜研究