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组织状态对45CrNiMoVA钢超声滚压表面完整性的影响∗

  • 栾晓圣1

    机 构：

    1. 北京理工大学机械与车辆工程学院 北京 100081

    ×
  • ， 梁志强2

    机 构：

    2. 北京理工大学先进加工技术国防重点学科实验室 北京 100081

    ×
  • ， 赵文祥2

    机 构：

    2. 北京理工大学先进加工技术国防重点学科实验室 北京 100081

    ×
  • ， 陈一帆1

    机 构：

    1. 北京理工大学机械与车辆工程学院 北京 100081

    ×
  • ， 李宏伟3

    机 构：

    3. 北京北方车辆集团有限公司 北京 100072

    ×
  • ， 刘心藜3

    机 构：

    3. 北京北方车辆集团有限公司 北京 100072

    ×
  • ， 周天丰2

    机 构：

    2. 北京理工大学先进加工技术国防重点学科实验室 北京 100081

    ×
  • ， 王西彬2

    机 构：

    2. 北京理工大学先进加工技术国防重点学科实验室 北京 100081

    ×

1. 北京理工大学机械与车辆工程学院 北京 100081；
2. 北京理工大学先进加工技术国防重点学科实验室 北京 100081；
3. 北京北方车辆集团有限公司 北京 100072；

Effect of Microstructure on Surface Integrity of 45CrNiMoVA Steel by Ultrasonic Surface Rolling Process

  • LUAN Xiaosheng1

    Affiliation：

    1. School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081 , China

    ×
  • ， LIANG Zhiqiang2

    Affiliation：

    2. Key Laboratory of Fundamental Science for Advanced Machining, Beijing Institute of Technology, Beijing 100081 , China

    ×
  • ， ZHAO Wenxiang2

    Affiliation：

    2. Key Laboratory of Fundamental Science for Advanced Machining, Beijing Institute of Technology, Beijing 100081 , China

    ×
  • ， CHEN Yifan1

    Affiliation：

    1. School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081 , China

    ×
  • ， LI Hongwei3

    Affiliation：

    3. Beijing North Vehicle Group Corporation, Beijing 100072 , China

    ×
  • ， LIU Xinli3

    Affiliation：

    3. Beijing North Vehicle Group Corporation, Beijing 100072 , China

    ×
  • ， ZHOU Tianfeng2

    Affiliation：

    2. Key Laboratory of Fundamental Science for Advanced Machining, Beijing Institute of Technology, Beijing 100081 , China

    ×
  • ， WANG Xibin2

    Affiliation：

    2. Key Laboratory of Fundamental Science for Advanced Machining, Beijing Institute of Technology, Beijing 100081 , China

    ×

1. School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081 , China；
2. Key Laboratory of Fundamental Science for Advanced Machining, Beijing Institute of Technology, Beijing 100081 , China；
3. Beijing North Vehicle Group Corporation, Beijing 100072 , China；

作者简介:

栾晓圣,男,1992年出生,博士研究生。主要研究方向为抗疲劳制造技术、材料动态力学行为。E-mail:1156781343@qq.com;

梁志强(通信作者),男,1984年出生,博士,副教授,博士研究生导师。主要研究方向为精密磨削、微细刀具设计与制造、抗疲劳制造技术。E-mail:liangzhiqiang@bit.edu.cn

中图分类号:TG306

DOI:10.11933/j.issn.1007-9289.20210328002

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目录contents

    摘要

    针对组织状态对超声滚压(USRP)表面完整性影响规律不明的问题,分别对铁素体+珠光体和回火马氏体两种组织状态下的 45CrNiMoVA 钢进行 USRP 试验,结合两种组织状态下材料动态力学性能的差异,对表面形貌及表面粗糙度、表层显微硬度、残余应力和表层微观组织进行对比分析。 结果表明,较软组织状态下的材料在 USRP 作用下更容易实现表面光整效果, 表层材料更容易发生塑性变形,导致形成更明显的表层硬化效果,但是难以形成更高幅值的残余压应力; USRP 在 45CrNiMoVA 钢表层引入的残余压应力幅值与其组织强度大小成正比,回火马氏体组织状态下表层残余压应力易呈“勺形”分布,最大残余压应力出现在亚表面,达到-1272 MPa,铁素体+珠光体组织状态下表层残余压应力易呈“梯度”分布,最大残余压应力出现在表面,达到-694 MPa;体心四方(BCT)晶体结构的组织在 USRP 作用下更容易发生晶粒细化,而体心立方(BCC) 晶体结构的组织在 USRP 作用下以塑性变形为主。 以上规律可用于指导不同组织状态下材料加工表面完整性的精准调控。

    Abstract

    To solve the problem that the effect of microstructure on the surface integrity of ultrasonic surface rolling process (USRP) is unclear, USRP tests were carried out on 45CrNiMoVA steel with ferrite + pearlite and tempered martensite respectively. The surface morphology, surface roughness, surface microhardness, residual stress, and surface microstructure were analyzed. The results show that the material with a soft phase is easier to achieve surface finishing effect under USRP, and the surface material is more prone to plastic deformation, resulting in a more obvious surface hardening effect, but it is difficult to form higher amplitude residual compressive stress. The results show that the magnitude of residual compressive stress introduced by USRP on the surface of 45CrNiMoVA steel is proportional to its microstructure strength. The residual compressive stress on the surface of 45CrNiMoVA steel is easy to be “ spoon-shaped” under tempered martensitic structure, and the maximum residual compressive stress appears on the subsurface, reaching -1272 MPa. The residual compressive stress on the surface of 45CrNiMoVA steel is easy to be “gradient” under ferrite + pearlite structure, the maximum residual compressive stress is -694 MPa on the surface. The results show that the structure of BCT crystal is more prone to grain refinement under the action of USRP, while the structure of BCC crystal is mainly plastic deformation under the action of USRP. The above rules can be used to guide the accurate regulation of material processing surface integrity under different microstructure states.

  • 0 前言

  • 超声滚压 ( Ultrasonic surface rolling process, USRP)是在传统表面滚压基础上增加超声振动,提高表面形变强化效率的一种高性能表面制造方法。它的原理是在静滚压力基础上,引入超声振动的 “声塑性效应[1-2] ”和“应变率效应[3-4] ”,促进表层材料产生更大、更深的塑性变形。大量研究结果已经表明, USRP能够在高强钢[5-6]、钛合金[7]、镁合金[8]、铝合金[9]、复合材料[10] 等关键结构件材料表面引入显著的残余压应力层,减小表面粗糙度值,使表层材料组织发生严重塑性变形( SPD),形成加工硬化、晶粒细化等效果,提高试样件的耐磨损、耐腐蚀和抗疲劳等性能。但是,大量USRP表面完整性研究结果存在明显的差异,表面完整性规律、水平不能有效统一对比,制约着USRP在实际生产中的有效运用。

  • 在工艺参数控制范围内,USRP表面完整性的水平主要受材料的组织状态及力学性能所影响[1-2]。马氏体组织状态下的材料往往形成难以饱和的残余压应力[5,13];而珠光体组织或奥氏体组织状态下的材料内部残余压应力具有明显的饱和性, 当其残余压应力超过一定的极限值会对结构造成损坏[14]。 YE等[15]对AISI 304不锈钢表面进行USRP, 测得其马氏体相残余压应力达到-1 400MPa,而奥氏体相残余压应力仅-400MPa。 ZHAO等[5] 发现300M钢(马氏体) USRP后表面残余压应力高达-1 879MPa。以上差异的主要原因在于残余应力的大小受材料的屈服强度和极限强度限制[16],淬火、回火后的马氏体具有高强度、高硬度特性,更适于形成大幅值残余压应力;较软相奥氏体和铁素体-珠光体组织对加工过程中局部塑性流动的抵抗力较小,这对残余应力的形成及稳定性有很大影响[17]。

  • 随着材料硬度的提高,表面形变处理对硬度的影响减小,在相同表面滚压条件下,淬火、回火试样表面硬度增加6%, 而退火试样表面硬度提高35%[12],这与不同组织状态下材料的塑性变形程度及其应变硬化指数不同有关;与铁素体-珠光体组织不同,奥氏体组织在严重塑性变形条件下还可能转变为马氏体,导致严重的应变硬化[18]。另外,根据Hall-Petch关系,材料的硬度变化还与晶粒细化有关[15]。塑性变形过程中的晶粒细化与材料的晶体结构密切关联,对具有体心立方(BCC)晶体结构和高堆垛层错能( SFE)的纯铁纳米化的研究表明, 位错壁和位错缠结通过位错滑移、产生、积累、长大、湮灭与重排,逐渐转变为具有小角度取向的亚晶界和高角度取向的晶界[19]。 SAKAI等[20] 指出堆垛层错能高的材料中,位错的重排和湮灭更容易发生,导致等轴亚晶的形成。 WANG等[21] 发现40Cr(铁素体和回火索氏体)在USRP作用下发生晶粒细化,表层形成大量等轴状纳米晶。 ZHANG等[22] 发现38CrSi钢(铁素体和珠光体组织) 表面激光冲击后形成高位错密度、位错环、位错墙和位错胞。 LIU等[6]在具有体心四方(BCT)结构的马氏体17-4PH不锈钢的纳米晶化过程中发现位错运动仍然是主要机制,同时孪晶和位错之间的相互作用影响了纳米板条微结构的细化,导致了等轴纳米晶粒的形成,但对较大晶粒变形的贡献却很小。 ZHAO等[5] 发现300M钢(BCT)USRP后板条马氏体明显细化,TEM观察到大量位错缠结和堆积现象。而在具有面心立方(FCC)结构的奥氏体不锈钢中,晶粒细化的形成是由于动态再结晶和孪生[23],YE等[15] 认为马氏体相变和孪晶的协同作用促进了表面纳米晶化。 NIKITIN等[24] 在奥氏体不锈钢滚压表层中也发现了纳米晶层,并且存在马氏体相变和孪晶。

  • 以上总结发现,组织状态的差异是导致USRP表面完整性规律无法统一、效果参差不齐的主要原因。揭示组织状态对USRP表面完整性的影响规律,对于指导实际生产中不同组织状态下材料的USRP工艺设计具有重要意义。目前针对同一材料不同组织状态下USRP表面完整性规律的研究鲜有报道。本文以45CrNiMoVA钢为研究对象,分别对其铁素体+珠光体和回火马氏体两种组织状态下的试样进行USRP试验,结合材料动态力学性能的差异,揭示表面形貌及表面粗糙度、残余应力、显微硬度和微观组织受试样组织状态的影响规律。

  • 1 试验方案

  • 1.1 试样材料

  • 试样材料是一种中碳低合金结构钢,其牌号为45CrNiMoVA,其化学成分列于表1,分别取其退火处理后和高温淬火+低温回火处理后的棒料进行USRP试验,退火处理后的试样组织形貌如图1a所示,为等轴状铁素体相(BCC晶体结构)和珠光体相的混合组织,其中珠光体相是由铁素体和渗碳体彼此相间呈层状排列所构成;高温淬火+低温回火处理后试样组织形貌如图1b所示,为细密、均匀分布的板条状回火马氏体(BCT晶体结构) 和少量的残余奥氏体,其力学性能参数列于表2。两种组织状态决定了试样存在显著的力学性能差异。

  • 表1 45CrNiMoVA钢化学成分(质量分数,GB/T3077-2015)

  • Table1 Chemical composition of 45CrNiMoVA steel(wt.%, GB/T3077-2015)

  • 图1 不同热处理条件下45CrNiMoVA钢微观组织形貌

  • Fig.1 Microstructure of 45CrNiMoVA steel under different heat treatment conditions

  • 表2 45CrNiMoVA钢力学性能参数[25]

  • Table2 Mechanical properties of 45CrNiMoVA steel

  • USRP过程中,工件表层材料受到动态冲击力的作用,发生高应变率变形[ 26-27]。通过霍普金森压杆( SHPB) 试验分别获得两种组织状态下45CrNiMoVA钢在高应变率下的真实应力-应变曲线(试样尺寸为 ϕ2mm×2mm,试样表面精磨, 应变率控制在2 000~4 000s),结果如图2a、2b所示。两种组织状态下材料真实应力-应变曲线的流动应力阶段力学行为差异明显,铁素体+珠光体组织状态下材料表现出明显的应变硬化行为,而回火马氏体组织状态下材料表现出动态平衡、流动应力稳定变化的行为。为了控制应变率,试样变形没有达到断裂状态,基于两种组织状态下材料真实应力应变曲线流动应力阶段的变化趋势可以推测铁素体 +珠光体组织状态下材料真实应力变化未达到强度极限,如果加载持续,其真实应力会进一步增加;而回火马氏体组织状态下材料真实应力变化基本达到强度极限。

  • 分别从3条真实应力应变曲线中取产生0.2%残余应变时的应力值为屈服强度 σs,取最大应力值为极限强度 σbc,计算平均值,得到铁素体+珠光体和回火马氏体两种组织状态下的动态力学性能参数,列于表3。回火马氏体相组织的试样屈服强度远高于铁素体+珠光体组织的试样,表现出超高强度特性;相比于表2准静态下的力学性能参数,高应变率回火马氏体组织状态下45CrNiMoVA钢的屈服强度和极限强度更高,这对其表面形变强化处理构成较大挑战。

  • 图2 不同组织状态的45CrNiMoVA钢高应变率下的真实应力-应变曲线

  • Fig.2 True stress-true strain curves of 45CrNiMoVA steel with different microstructure states at high strain rate

  • 表3 不同组织状态下45CrNiMoVA钢动态力学性能参数

  • Table3 Dynamic mechanical properties of 45CrNiMoVA steel with different microstructure

  • 1.2 试验方法及原理

  • 图3 所示为USRP试验及原理示意图。 USRP过程中表面材料凸起部分受滚压力作用向周边发生塑性流动,改变了原先的表面几何轮廓,趋向平面化,实现表面光整效果;表面材料弹塑性变形过程中会对相邻区域内材料产生相互作用力,亚表面材料随之产生应力-应变,造成微观组织的形变,而超声振动引入的高频动载荷作用,会促进塑性变形的发生[1-2],提高变形应变率,影响材料形变性能;基于赫兹接触理论,残余应力的形成与滚压卸载过程中材料的反向屈服、硬化有关,卸载后应力不能完全释放,在表层形成残余压应力[16]。

  • 分别对相同直径(ϕ42mm),不同组织状态下的45CrNiMoVA钢圆棒表面进行USRP试验。试验前试样表面采用优化过的工艺参数进行车削,铁素体+珠光体组织状态下的45CrNiMoVA钢试样车削工艺参数为:工件转速 n=400r/min,进给速度v f=0.3mm/r,车削深度a p=0.1mm;回火马氏体组织状态下的45CrNiMoVA钢试样车削工艺参数为:工件转速 n=400r/min,进给速度v f=0.1mm/r,车削深度a p=0.1mm。 USRP试验参数列于表4,滚球材料为硬质合金,其半径为7mm,采用激光位移传感器测量该试验设备的超声振动信号,测得的频率 f 为27 376Hz,振幅能够达到的最大值为9.35 μm, 如图4所示,本次试验设定的超声振幅为7 μm。

  • 图3 USRP试验过程原理示意图

  • Fig.3 Schematic diagram of USRP

  • 表4 不同组织状态下45CrNiMoVA钢USRP试验参数

  • Table4 Experimental parameters of USRP for 45CrNiMoVA steel with different microstructure

  • 图4 空载下的超声振动信号

  • Fig.4 Ultrasonic vibration signal under no load

  • 表面完整性检测方法如下:采用基恩士显微镜 (型号为VK-X100)对试样表面形貌进行检测,并按照GBT1031—2009测量表面粗糙度 Ra。采用X射线衍射仪(型号为X-350)和电解抛光的方法逐层测量残余应力。参数包含:倾斜固定 ψ 法,交相关法定峰,靶材Cr-kα,ψ 角0°、45°,衍射晶面(211), 管电压20kV,管电流5mA,扫描范围145°~168°, 步距0.2°。从超声滚压后的试样上取样,抛光、腐蚀(4%浓度硝酸酒精),观测强化表层横截面微观组织形貌,并在该横截面上采用显微硬度计测量表层显微硬度沿层深分布。

  • 2 结果与讨论

  • 2.1 表面形貌及表面粗糙度

  • 图5 所示为铁素体 + 珠光体组织状态下45CrNiMoVA钢USRP前后的表面形貌,USRP前表面为车削形成的“沟槽”纹理,可以发现“沟槽”表面凹凸不平,如图5a所示,这是因为在混合组织状态下,铁素体相(较软)和珠光体相(较硬)力学性能的差异导致切削性能稳定性较差所引起;USRP后,表面“沟槽” 纹理基本消失,趋于平面化,如图5b所示。回火马氏体组织状态下45CrNiMoVA钢USRP前后的表面形貌如图6所示,USRP前试样表面同样是车削形成的“沟槽” 纹理,如图6a所示;USRP后,产生“削峰填谷”效果,表面趋于平整,但仍存在 “沟槽”的痕迹,如图6b所示,这是因为回火马氏体组织的超高强度特性使其具有更大的塑性变形抵抗力,为了进一步提升表面光整效果,可采取增大静滚压力或增大超声振幅的措施。而铁素体+珠光体组织状态下材料的屈服强度较低,表面材料更容易发生塑性流动,导致其USRP表面光整效果更好,但也需要注意过度塑性变形,可能导致表层材料过度硬化而出现层裂、脱落现象[14]。

  • 图5 铁素体+珠光体组织状态下45CrNiMoVA钢USRP前后表面形貌

  • Fig.5 Surface morphology of 45CrNiMoVA steel with ferrite and pearlite before and after USRP

  • 图6 回火马氏体组织状态下45CrNiMoVA钢USRP前后表面形貌

  • Fig.6 Surface morphology of 45CrNiMoVA steel with tempered martensite before and after USRP

  • 图7 所示为两种组织状态下45CrNiMoVA钢USRP前后表面粗糙度变化,USRP导致铁素体+珠光体组织状态下的试样表面粗糙度 Ra 减小87.5%,回火马氏体组织状态下的试样表面粗糙度 Ra 减小46.6%。可见,较软相(铁素体+珠光体)组织状态下的试样经USRP作用后的表面光整效果更好。

  • 图7 两种组织状态下45CrNiMoVA钢USRP前后表面粗糙度变化

  • Fig.7 Surface roughness changes of 45CrNiMoVA steel with different microstructure before and after USRP

  • 2.2 表层残余应力

  • 图8 所示为两种组织状态下45CrNiMoVA钢USRP前后表层残余应力(轴向)沿深度方向的分布规律。相比于USRP前表层残余应力状态,USRP后表层残余压应力幅值和影响层深度都大幅增加, 并且两种组织状态下的残余压应力影响层深度相差不大,皆在0.5mm左右。 USRP后铁素体+珠光体组织状态下的试样表层残余压应力呈梯度分布,最大值出现在表面,达到-694MPa,沿深度方向递减; 而回火马氏体组织状态下的试样表层残余压应力最大值出现在亚表层,达到-1 272MPa,呈典型的“勺形”分布,沿深度方向先增大、后减小。赫兹(Hertz) 接触加载下的弹塑性变形理论可以解释两种组织状态下试样表现出不同残余压应力分布特征的原因[16,28]。在相同USRP参数下,强度较低的试样 (铁素体+珠光体)表层材料受到足够的加载力,卸载过程中表层材料直接进入反向屈服、硬化的变形阶段;而强度较高的试样(回火马氏体)在USRP后的卸载过程中,表层材料是反向弹性变形阶段,而亚表层是反向屈服、硬化阶段,导致其残余压应力幅值出现在亚表层,如果加载力足够大,超高强度材料表层最大残余压应力也有可能转移到表面[5]。

  • 图8 两种组织状态下45CrNiMoVA钢USRP前后表层残余应力(轴向)分布规律

  • Fig.8 Distribution of residual stress in the surface layer of 45CrNiMoVA steel with different microstructure before and after USRP

  • 2.3 表层硬化与微观组织变形

  • 图9 所示为两种组织状态下45CrNiMoVA钢USRP前后表层显微硬度沿深度方向的分布规律。对于铁素体+珠光体组织状态下的试样基体显微硬度HV0.3在252~268范围内波动,USRP前试样表层材料受到车削的影响,导致轻微的硬化;经USRP后,表层硬化形成明显的梯度分布,最大显微硬度值出现在表面,高达310,如图9a所示。对于回火马氏体组织状态下的试样基体显微硬度HV0.3在658~667范围内波动,USRP前试样表层显微硬度几乎不受车削的影响;经USRP后,表层显微硬度略微提升,最大值达到674,如图9b所示。对比两种组织状态下试样表层显微硬度受USRP的影响发现,铁素体+珠光体组织状态下的试样表层显微硬度提升更为明显,硬化层深度也更大,这是因为在相同USRP工艺参数下,屈服强度越低的材料发生的塑性变形越大,另外,基于第1.1节图2的数据分析,铁素体+珠光体组织状态下的试样材料在变形过程中的应变硬化效应更明显;而超高强度材料难以产生较大的塑性变形,回火马氏体组织状态下的试样材料在变形过程中应变硬化效应不明显,导致其表层硬化效果较弱,采用更小的滚压头或增加滚压道次被证明能够有效促进表层硬化[5,21]。

  • 图9 两种组织状态下45CrNiMoVA钢USRP前后表层显微硬度分布规律

  • Fig.9 Distribution of surface microhardness of 45CrNiMoVA steel with different microstructure before and after USRP

  • 图10 所示为铁素体 + 珠光体组织状态下45CrNiMoVA钢USRP后表层横截面微观组织形貌, 表层形成大约0.2mm深的严重塑性变形层,该变形引起的加工硬化与图9a中表层显微硬度明显增大相对应。 BCC晶体结构有大量的滑移系统和高的堆垛层错能可以支撑位错运动,导致该变形层内部形成大量位错缠结、位错墙, 使显微硬度增加[20,22,29]。从图10b中可以发现等轴状晶粒受挤压发生扭曲变形。而回火马氏体组织状态下的试样USRP后表层横截面在图11所示尺度下没有发现明显的塑性变形层。这种组织状态不同引起塑性变形层差异的类似结果在ABRAO的表面深滚研究中也可以发现[12]。

  • 图10 铁素体+珠光体组织状态下45CrNiMoVA钢USRP后表层横截面微观组织形貌

  • Fig.10 Microstructure of surface layer cross section of 45CrNiMoVA steel with ferrite and pearlite after USRP

  • 图11 回火马氏体组织状态下45CrNiMoVA钢USRP后表层横截面微观组织形貌

  • Fig.11 Microstructure of surface layer cross section of 45CrNiMoVA steel with tempered martensite after USRP

  • 进一步放大观察USRP后表层横截面微观组织,如图12所示,可以发现铁素体+珠光体组织状态下45CrNiMoVA钢USRP后的铁素体相内部混入了渗碳体颗粒,如图12a所示,珠光体内部的渗碳体(亮色的薄层) 脆性较大,在USRP的强烈挤压作用下破碎, 被挤入了铁素体内部。 TONG等[ 30] 认为高应变率、大变形是导致渗碳体断裂、分离的主要原因。在回火马氏体组织状态下的试样表层横截面观察到大约2 μm深的“ 白层”,如图12b所示,这种“ 白层” 内部被认为发生了晶粒细化,形成了纳米晶,高应变率下的严重塑性变形是导致晶粒细化的原因[ 31-32]。对比发现,相比于BCC晶体结构的组织状态,BCT晶体结构下的组织状态在USRP作用下似乎更容易发生晶粒细化[ 6,22,29,33]。

  • 图12 两种组织状态下45CrNiMoVA钢USRP后表层横截面SEM微观组织形貌对比

  • Fig.12 Comparison of surface microstructure deformation of 45CrNiMoVA steel with different microstructure states after USRP

  • 3 结论

  • (1) 较软相组织状态的材料在USRP作用下更容易实现表面光整效果,表层材料更容易发生塑性变形,导致形成更明显的表层硬化,但是难以形成更高幅值的残余压应力。

  • (2) USRP引入的残余压应力幅值与材料组织强度大小成正比,高强度组织状态下USRP更容易引入呈“勺形”分布的残余压应力,残余压应力幅值出现在亚表面,而低强度组织状态下USRP更容易引入呈“梯度”分布的残余压应力,残余压应力幅值出现在表面。

  • (3) BCT晶体结构的组织在USRP作用下更容易发生晶粒细化,而BCC晶体结构的组织在USRP作用下以位错缠结、位错墙的形式吸收更多外部能量,形成更深的塑性变形层。

  • (4) 基于上述规律分析,针对工件材料组织状态及其力学性能,设计与其相匹配的USRP工艺是实现表面完整性调控的重要手段。

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  • 基本信息

    中图分类号: TG306
    DOI: 10.11933/j.issn.1007-9289.20210328002

    基金信息

    国家重点研发计划(2019YFB1311100)；
    基础科研(DEDPHF, DEDPZF, DEDPYDJ, JCKY2017208C005)；
    国家自然科学基金(51975053) 资助项目；
    Supported by National Key Research and Development Program of China(2019YFB1311100)；
    Industrial Technology Development Program of China(DEDPHF, DEDPZF, DEDPYDJ, JCKY2017208C005)；
    National Natural Science Foundation of China (51975053).；

    引用信息

    稿件历史

    收稿日期: 2021-03-28

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