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定向再结晶过程中的异常晶粒长大行为及机理研究

项目来源

国家自然科学基金(NSFC)

项目主持人

崔烨

项目受资助机构

哈尔滨工程大学

项目编号

51701051

立项年度

2017

立项时间

未公开

项目级别

国家级

研究期限

未知 / 未知

受资助金额

24.00万元

学科

工程与材料科学-金属材料-金属材料制备与加工

学科代码

E-E01-E0102

基金类别

青年科学基金项目

关键词

异常晶粒长大 ; 晶界结构 ; 定向再结晶 ; 晶界迁移 ; 机理 ; Directional recrystallization ; Grain boundary migration ; Mechanism ; Grain boundary structure ; Abnormal grain growth

参与者

张洋；陈丹；郭浩；牛建坤；马慧君；陈明江

参与机构

哈尔滨工程大学

项目标书摘要：晶粒的异常长大普遍出现在变形金属材料热处理过程中，其机理是材料科学中一个经典而又没有解决的问题，晶界的选择性迁移是决定该过程的关键因素。本项目提出通过分析定向再结晶过程中的晶界定向迁移过程研究晶界的选择性迁移，进而深化对于晶粒的异常长大机理的认识。本项目采用变形/热处理工艺制备具有特定初始结构的纯金属/合金材料，对比具有不同初始结构的纯金属/合金在经历不同定向再结晶工艺处理前后材料的微观组织结构，研究不同热处理工艺条件下材料组织结构的演化规律，分析计算不同结构晶界的临界粗化温度、表观激活能和晶界迁移率，研究定向再结晶过程中的不同晶界定向迁移行为。并探索温度场、合金成分、晶界结构、第二相粒子分布等因素对于定向再结晶过程中晶界定向迁移的影响规律其机制，揭示定向再结晶过程中晶界定向迁移对异常晶粒长大影响机理，为采用定向再结晶工艺设计材料组织和界面结构提供理论基础。

Application Abstract: The abnormal growth of grain is usually found in the process of heat treatment of deformed metal materials.However,its mechanism is a classic but unsolved problem in material science.The selective migration of grain boundary is the key factor to determine the process.This project studies the selective migration of grain boundaries by analyzing the grain boundary directional migration in the process of directional recrystallization,and thus deepens the understanding of the mechanism of abnormal growth of grain.In this project,deformation/heat treatment process is used to prepare pure metals/alloys with specific initial structures and to contrast the microstructure of metals/alloys with different initial structures before and after different directional recrystallization processes.The evolution of the material structure under different heat treatment conditions is studied;the critical coarsening temperature,apparent activation energy and mobility of grain boundaries are analyzed and calculated;the directional migration of different grain boundaries in the process of directional recrystallization is studied.Through the study of the effect and mechanism of temperature field,alloy composition,grain boundary structure and second phase particle distribution,the Influence mechanism of grain directional migration on abnormal grain growth during directional recrystallization is revealed and thus provides the theoretical basis for the design of material structure and interface structure by directional recrystallization.

项目受资助省

黑龙江省

项目结题报告(全文)

晶粒的异常长大普遍出现在变形金属材料热处理过程中，其机理是材料科学中一个经典而又没有解决的问题。本项目提出通过分析定向再结晶过程中的晶界定向迁移研究晶界的选择性迁移，进而深化对于晶粒的异常长大机理的认识。本项目分析了合金预处理和定向再结晶工艺参数对于定向再结晶过程中晶粒异常长大行为的影响，分析了定向再结晶过程中的驱动力，获得了不同热区温度对于晶界迁移速率的影响，阐明了定向再结晶过程中晶界定向迁移和晶粒选择性长大机制。本项目研究发现对于Cu基/Fe基超弹性合金，热区温度必须要特定温度以上，才能获得大的长径比的柱状晶结构，热区温度低于该温度的情况下，不能提供足够的驱动力促使晶界发生沿温度梯度方向的定向迁移，所获得的晶粒为长径比较小的柱状晶或等轴晶。该温度与合金的析出相固溶温度接近，说明析出相是制约超弹性合金晶界选择性迁移的重要因素。研究发现定向再结晶的驱动力主要由晶粒尺寸差提供，位错能量会在析出相形核长大过程中消耗，因此对于晶粒异常长大影响较小。CuAlMn合金在800、850和900℃的热区温度下获得最大长径比的柱状晶的抽拉速率分别为2、5和15μm/s。说明较高的热区温度更有利于提高晶界定向迁移速率。本项目系统研究了定向再结晶工艺对于CuAlMn和FeMnAlNi超弹性合金的影响，发现适合高效制备大尺寸CuAlMn和FeMnAlNi超弹性合金柱状晶/单晶的定向再结晶工艺分别为热区温度为900℃、抽拉速率为15μm/s和热区温度为1200℃、抽拉速率为10μm/s。本项目提出利用定向再结晶技术控制超弹性合金晶粒结构从而获得高性能的Cu基/Fe基超弹性合金，阐明了定向再结晶工艺控制超弹性合金异常晶粒长大机理，获得了大尺寸晶粒Cu基/Fe基超弹性合金，获得的超弹性合金具有优异的力学性能。为定向再结晶工艺用于开发高性能合金材料开辟了新方向。本项目为定向再结晶工艺向实际生产发展和开发高性能超弹性合金奠定基础。

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  • 1.Nanoprecipitate-Strengthened High-Entropy Alloys

    • 关键词：
    • alloy design; high-entropy alloys; mechanical properties;nanoprecipitates; precipitation strengthening;MECHANICAL-PROPERTIES; STAINLESS-STEEL; TENSILE PROPERTIES;SOLID-SOLUTION; MICROSTRUCTURAL EVOLUTION; NANOSCALE PRECIPITATION;DEFORMATION-BEHAVIOR; CORROSION BEHAVIOR; SLUGGISH DIFFUSION;THERMAL-STABILITY

    Multicomponent high-entropy alloys (HEAs) can be tuned to a simple phase with some unique alloy characteristics. HEAs with body-centered-cubic (BCC) or hexagonal-close-packed (HCP) structures are proven to possess high strength and hardness but low ductility. The faced-centered-cubic (FCC) HEAs present considerable ductility, excellent corrosion and radiation resistance. However, their strengths are relatively low. Therefore, the strategy of strengthening the ductile FCC matrix phase is usually adopted to design HEAs with excellent performance. Among various strengthening methods, precipitation strengthening plays a dazzling role since the characteristics of multiple principal elements and slow diffusion effect of elements in HEAs provide a chance to form fine and stable nanoscale precipitates, pushing the strengths of the alloys to new high levels. This paper summarizes and review the recent progress in nanoprecipitate-strengthened HEAs and their strengthening mechanisms. The alloy-design strategies and control of the nanoscale precipitates in HEAs are highlighted. The future works on the related aspects are outlined.

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