本文主要研究内容
作者丁志义（2019）在《Ni-Mn-Ga(Co,Cu)形状记忆合金微丝多场下物理性能研究》一文中研究指出：化学成分接近标准化学计量比的Ni2MnGa磁性形状记忆合金是一种对温度场,力场和磁场敏感的新型智能材料,在多场下表现出多功能特性,如形状记忆效应、超弹性、磁致应变及磁热效应等,这些特性为设计和开发多功能器件提供选择。但该体系块体合金具有本征脆性,难加工,而单晶的制备耗时成本高,制约了形状记忆合金的发展和工业应用。本文采用玻璃包覆法制备Ni-Mn-Ga(Co,Cu)合金微丝,通过快速凝固,晶粒调控来改善其力学性能。在此基础上,系统研究了合金微丝的微观结构、超弹性、马氏体相变、Wiedemann effect、力磁耦合条件下的磁致扭转及声发射行为,以通过性能研究和理论探索来发现新规律和新现象,为优化合金性能和多功能设计提供实验和理论依据。(1)初步研究了合金微丝超弹性、形状记忆效应、应力诱发马氏体相变。利用玻璃包覆法将块体合金制备成微丝,直径在15-400μm。研究发现室温为奥氏体相Ni53Mn24Ga23(at.%)合金微丝,在循环拉伸测试中获得高达14%可恢复应变,～10%超弹性应变,表现出优异的机械稳定性。大应变和超弹得益于应力诱发马氏体相变。转变临界应力随着循环次数的增加逐渐减小至趋于稳定,具有“训练”效应。这种力学性能的改善得益于合金丝材具有大的自由表面,减少晶界约束从而提高晶粒之间的协调变形能力。(2)系统研究了合金微丝在力温耦合下的多步超弹和多步相变行为。在提高力学性能的基础上,系统研究了 Ni-Mn-Ga和Ni-Mn-Ga-Co-Cu多晶形状记忆合金微丝的组织结构、微结构和机械性能,并集中研究了力-温耦合下合金微丝的马氏体和中间马氏体相变行为。发现室温分别为奥氏体相和马氏体相的Ni-Mn-Ga和Ni-Mn-Ga-Co-Cu合金微丝在不同温度拉伸时在应力应变曲线上出现多步台阶行为。通过原位的TEM和XRD表征证实是应力诱发的多步相变行为(存在中间马氏体相变)。具有<001>择优取向Ni-Mn-Ga形状记忆合金微丝在213-300K温度范围内,展现了四种一步或多步马氏体相变顺序,即P→nM(n=2,5,7)和5M→7M→NM。随后通过Co,Cu元素替代Ni和Mn,拓宽和提高了相变温度窗口。在263-533K的拉伸应力应变曲线也出现多步超弹行为。根据临界应力随温度变化建立了力温耦合下临界应力-温度相图。形状记忆合金微丝的多步转变得益于微丝竹节状形态,超弹性能接近单晶,这可大大降低合金微丝在微器件方面应用成本。这一结果对马氏体相变理论研究和实际应用具有重大意义。(3)阐明了奥氏体相合金微丝的预马氏体相变行为。形状记忆合金的力学性能与微观组织结构的演变密切相关。室温为奥氏体相Ni-Mn-Ga微丝主衍射点周围存在卫星斑点,合金具有超晶格结构。卫星斑在TEM上对应“花呢结构”是一种预马氏体相变特征。通过HRTEM分析单畴和多畴结构发现是有序的原子堆垛组成。当温度低于Ms时,多种畴结构转变为具有条纹特征的五层调制马氏体结构。通过实验获得了在冷却过程中,马氏体相变次序为P→PM→M。在原子尺度上验证了由低温引起的结构转变,有助于深度了解马氏体相变过程和先进形状记忆合金设计。(4)磁性形状记忆合金微丝扭转行为探索:魏德曼效应、力致扭转和磁致扭转。分别开展了室温为奥氏体相和马氏体相微丝的扭转行为这一功能特性研究。利用光杠杆法首先研究合金微丝在周向和轴向磁场下的魏德曼扭转,在～10 Oe周向磁场中获得234”/cm的扭转角。其次结合微丝的应力诱发相变特性发现合金微丝力场作用下也出现扭转行为:力致扭转,测得扭转角为θ/l=1250”/cm。随后在力致扭转的基础上引入旋转磁场,系统研究了合金微丝在两种模式、力磁耦合下的磁致扭转行为,明确了力磁耦合条件下扭转角与磁场大小、方向以及静态力之间的耦合关系。(5)形状记忆合金微丝的声发射特性研究。发现合金微丝在拉伸时有声响可闻,随后利用动态信号分析仪系统研究马氏体相变过程中不同直径合金微丝的声发射频谱和截止频率特性。对声发射频谱分析发现,声发射频率集中在特定的频率范围内,反映了合金微丝在拉伸应力诱发相变过程中原子集体运动的特性。同时,发现形状记忆合金微丝越细,截止频率值越大。本文研究Ni-Mn-Ga(Co,Cu)形状记忆合金微丝材在力场、温度场和磁场作用下的微观结构演变与性能之间的依赖关系,为合金设计和探索高性能合金提供理论指导和实践意义。同时,探索微丝扭转行为和声发射特性为合金的工程应用提供技术支持。
Abstract
hua xue cheng fen jie jin biao zhun hua xue ji liang bi de Ni2MnGaci xing xing zhuang ji yi ge jin shi yi chong dui wen du chang ,li chang he ci chang min gan de xin xing zhi neng cai liao ,zai duo chang xia biao xian chu duo gong neng te xing ,ru xing zhuang ji yi xiao ying 、chao dan xing 、ci zhi ying bian ji ci re xiao ying deng ,zhe xie te xing wei she ji he kai fa duo gong neng qi jian di gong shua ze 。dan gai ti ji kuai ti ge jin ju you ben zheng cui xing ,nan jia gong ,er chan jing de zhi bei hao shi cheng ben gao ,zhi yao le xing zhuang ji yi ge jin de fa zhan he gong ye ying yong 。ben wen cai yong bo li bao fu fa zhi bei Ni-Mn-Ga(Co,Cu)ge jin wei si ,tong guo kuai su ning gu ,jing li diao kong lai gai shan ji li xue xing neng 。zai ci ji chu shang ,ji tong yan jiu le ge jin wei si de wei guan jie gou 、chao dan xing 、ma shi ti xiang bian 、Wiedemann effect、li ci ou ge tiao jian xia de ci zhi niu zhuai ji sheng fa she hang wei ,yi tong guo xing neng yan jiu he li lun tan suo lai fa xian xin gui lv he xin xian xiang ,wei you hua ge jin xing neng he duo gong neng she ji di gong shi yan he li lun yi ju 。(1)chu bu yan jiu le ge jin wei si chao dan xing 、xing zhuang ji yi xiao ying 、ying li you fa ma shi ti xiang bian 。li yong bo li bao fu fa jiang kuai ti ge jin zhi bei cheng wei si ,zhi jing zai 15-400μm。yan jiu fa xian shi wen wei ao shi ti xiang Ni53Mn24Ga23(at.%)ge jin wei si ,zai xun huan la shen ce shi zhong huo de gao da 14%ke hui fu ying bian ,～10%chao dan xing ying bian ,biao xian chu you yi de ji xie wen ding xing 。da ying bian he chao dan de yi yu ying li you fa ma shi ti xiang bian 。zhuai bian lin jie ying li sui zhao xun huan ci shu de zeng jia zhu jian jian xiao zhi qu yu wen ding ,ju you “xun lian ”xiao ying 。zhe chong li xue xing neng de gai shan de yi yu ge jin si cai ju you da de zi you biao mian ,jian shao jing jie yao shu cong er di gao jing li zhi jian de xie diao bian xing neng li 。(2)ji tong yan jiu le ge jin wei si zai li wen ou ge xia de duo bu chao dan he duo bu xiang bian hang wei 。zai di gao li xue xing neng de ji chu shang ,ji tong yan jiu le Ni-Mn-Gahe Ni-Mn-Ga-Co-Cuduo jing xing zhuang ji yi ge jin wei si de zu zhi jie gou 、wei jie gou he ji xie xing neng ,bing ji zhong yan jiu le li -wen ou ge xia ge jin wei si de ma shi ti he zhong jian ma shi ti xiang bian hang wei 。fa xian shi wen fen bie wei ao shi ti xiang he ma shi ti xiang de Ni-Mn-Gahe Ni-Mn-Ga-Co-Cuge jin wei si zai bu tong wen du la shen shi zai ying li ying bian qu xian shang chu xian duo bu tai jie hang wei 。tong guo yuan wei de TEMhe XRDbiao zheng zheng shi shi ying li you fa de duo bu xiang bian hang wei (cun zai zhong jian ma shi ti xiang bian )。ju you <001>ze you qu xiang Ni-Mn-Gaxing zhuang ji yi ge jin wei si zai 213-300Kwen du fan wei nei ,zhan xian le si chong yi bu huo duo bu ma shi ti xiang bian shun xu ,ji P→nM(n=2,5,7)he 5M→7M→NM。sui hou tong guo Co,Cuyuan su ti dai Nihe Mn,ta kuan he di gao le xiang bian wen du chuang kou 。zai 263-533Kde la shen ying li ying bian qu xian ye chu xian duo bu chao dan hang wei 。gen ju lin jie ying li sui wen du bian hua jian li le li wen ou ge xia lin jie ying li -wen du xiang tu 。xing zhuang ji yi ge jin wei si de duo bu zhuai bian de yi yu wei si zhu jie zhuang xing tai ,chao dan xing neng jie jin chan jing ,zhe ke da da jiang di ge jin wei si zai wei qi jian fang mian ying yong cheng ben 。zhe yi jie guo dui ma shi ti xiang bian li lun yan jiu he shi ji ying yong ju you chong da yi yi 。(3)chan ming le ao shi ti xiang ge jin wei si de yu ma shi ti xiang bian hang wei 。xing zhuang ji yi ge jin de li xue xing neng yu wei guan zu zhi jie gou de yan bian mi qie xiang guan 。shi wen wei ao shi ti xiang Ni-Mn-Gawei si zhu yan she dian zhou wei cun zai wei xing ban dian ,ge jin ju you chao jing ge jie gou 。wei xing ban zai TEMshang dui ying “hua ne jie gou ”shi yi chong yu ma shi ti xiang bian te zheng 。tong guo HRTEMfen xi chan chou he duo chou jie gou fa xian shi you xu de yuan zi dui duo zu cheng 。dang wen du di yu Msshi ,duo chong chou jie gou zhuai bian wei ju you tiao wen te zheng de wu ceng diao zhi ma shi ti jie gou 。tong guo shi yan huo de le zai leng que guo cheng zhong ,ma shi ti xiang bian ci xu wei P→PM→M。zai yuan zi che du shang yan zheng le you di wen yin qi de jie gou zhuai bian ,you zhu yu shen du le jie ma shi ti xiang bian guo cheng he xian jin xing zhuang ji yi ge jin she ji 。(4)ci xing xing zhuang ji yi ge jin wei si niu zhuai hang wei tan suo :wei de man xiao ying 、li zhi niu zhuai he ci zhi niu zhuai 。fen bie kai zhan le shi wen wei ao shi ti xiang he ma shi ti xiang wei si de niu zhuai hang wei zhe yi gong neng te xing yan jiu 。li yong guang gang gan fa shou xian yan jiu ge jin wei si zai zhou xiang he zhou xiang ci chang xia de wei de man niu zhuai ,zai ～10 Oezhou xiang ci chang zhong huo de 234”/cmde niu zhuai jiao 。ji ci jie ge wei si de ying li you fa xiang bian te xing fa xian ge jin wei si li chang zuo yong xia ye chu xian niu zhuai hang wei :li zhi niu zhuai ,ce de niu zhuai jiao wei θ/l=1250”/cm。sui hou zai li zhi niu zhuai de ji chu shang yin ru xuan zhuai ci chang ,ji tong yan jiu le ge jin wei si zai liang chong mo shi 、li ci ou ge xia de ci zhi niu zhuai hang wei ,ming que le li ci ou ge tiao jian xia niu zhuai jiao yu ci chang da xiao 、fang xiang yi ji jing tai li zhi jian de ou ge guan ji 。(5)xing zhuang ji yi ge jin wei si de sheng fa she te xing yan jiu 。fa xian ge jin wei si zai la shen shi you sheng xiang ke wen ,sui hou li yong dong tai xin hao fen xi yi ji tong yan jiu ma shi ti xiang bian guo cheng zhong bu tong zhi jing ge jin wei si de sheng fa she pin pu he jie zhi pin lv te xing 。dui sheng fa she pin pu fen xi fa xian ,sheng fa she pin lv ji zhong zai te ding de pin lv fan wei nei ,fan ying le ge jin wei si zai la shen ying li you fa xiang bian guo cheng zhong yuan zi ji ti yun dong de te xing 。tong shi ,fa xian xing zhuang ji yi ge jin wei si yue xi ,jie zhi pin lv zhi yue da 。ben wen yan jiu Ni-Mn-Ga(Co,Cu)xing zhuang ji yi ge jin wei si cai zai li chang 、wen du chang he ci chang zuo yong xia de wei guan jie gou yan bian yu xing neng zhi jian de yi lai guan ji ,wei ge jin she ji he tan suo gao xing neng ge jin di gong li lun zhi dao he shi jian yi yi 。tong shi ,tan suo wei si niu zhuai hang wei he sheng fa she te xing wei ge jin de gong cheng ying yong di gong ji shu zhi chi 。
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论文作者分别是来自北京科技大学的丁志义，发表于刊物北京科技大学2019-01-16论文，是一篇关于合金论文,磁性形状记忆合金微丝论文,马氏体转变论文,磁致扭转论文,多场耦合论文,北京科技大学2019-01-16论文的文章。本文可供学术参考使用，各位学者可以免费参考阅读下载，文章观点不代表本站观点，资料来自北京科技大学2019-01-16论文网站，若本站收录的文献无意侵犯了您的著作版权，请联系我们删除。
标签：合金论文; 磁性形状记忆合金微丝论文; 马氏体转变论文; 磁致扭转论文; 多场耦合论文; 北京科技大学2019-01-16论文;