多晶磁控金属智能材料的高性能化及关键科学问题研究

The goal of this project is to develop polycrystalline Ni-Mn-X (X = Ga, In, Sn, Sb) based Heusler alloys with high magnetically-controlled performance, in light of the intrinsic magnetocrystalline anisotropy in single crystal form and the crystallographic anisotropy of martensitic variants. Based upon the integrated design of alloy composition, multi-scale structure and magnetically-controlled functionality, intelligent metallic materials with large magnetic-field-induced strains and superior magnetic-refrigeration capacity will be prepared through texturing and microstructural modification, assisted with cooperative training at external fields (magnetic field/stress field/thermal field). By using the space- resolved electron back scattering diffraction technique and the time/space- resolved high energy X-ray diffraction and neutron diffraction techniques, the variant configuration, interface character, martensitic transformation crystallography and microstructural morphology will be analyzed on complex modulated martensitic phases in polycrystalline alloys. Moreover, the effects of external fields on martensitic transformation, crystallographic texture, microstructural inheritance and magnetically-controlled performance, as well as possible mechanisms underlying such effects, are to be revealed, which would provide guidance for the development of new-generation intelligent materials with magnetically-controlled multi-functionality. In the course of the project execution, the research team will publish 40-50 scientific papers and apply 2-3 invention patents, and 5-8 graduate students involved in this project will receive their academic degrees.

本项目以NiMnX（X = Ga、In、Sn、Sb）基Heusler型合金为对象，利用该类合金固有的强磁晶各向异性以及马氏体变体的强晶体学各向异性，开展多晶金属磁控智能材料的高性能化及关键科学问题研究。主要包括：以多晶合金的织构化和微观组织调控为主线，以多外场（磁场/应力场/温度场）协同训练为关键手段，结合合金化学成分、跨尺度结构与磁控功能行为的一体化设计，制备磁致形状记忆与磁制冷性能优异的磁控智能材料；借助空间分辨的电子背散射衍射（EBSD）取向成像技术以及时空分辨的高能X射线衍射（HEXRD）、中子衍射（ND）技术等，解析多晶合金中具有复杂调制结构的马氏体的变体组态、界面特征以及马氏体转变晶体学、组织形貌学特征，阐明外场对多晶合金的马氏体转变、强取向化、微观组织遗传及磁控功能行为的作用机制，为研制新一代多功能金属磁控智能材料提供指导。结合项目实施，预期发表学术论文40-50篇，申请发明专利2-3件，培养研究生5-8人。

本项目以具有一级马氏体相变特征的NiMnX（X = Ga、In、Sn、Sb）基Heusler型多功能合金为对象，开展了多晶合金马氏体相变特性及相关功能行为调控的研究。借助空间分辨的电子背散射衍射取向成像技术以及时空分辨的高能X射线衍射、中子衍射技术等，解析了不同体系的多晶合金中复杂调制结构马氏体相的晶体结构、变体组态、界面特征以及马氏体转变晶体学、组织形貌学特征，阐明了温度场、应力场、磁场对多晶合金的马氏体转变、强取向化、微观组织遗传及磁控功能行为的作用机制，为研制新一代多功能磁控金属智能材料提供指导。在此基础上，以织构化与微结构调控为主线，结合第一性原理计算、化学成分与组织结构协同设计、外场训练处理等，突破了多晶NiMnX基合金高性能化、低成本化制备技术瓶颈，开发出了具有大磁致应变、高磁熵变及大绝热温变的原型合金，在智能传感驱动和固态制冷领域中有潜在应用的前景。自主设计并搭建了一套基于激光干涉法的高精度磁致应变测量装置，测量精度达0.2ppm。项目实施以来，共发表SCI期刊论文61篇，授权发明专利9件。