本文主要研究内容
作者陈磊（2019）在《第VB族过渡金属氮化物结构和物性的第一性原理研究》一文中研究指出：随着社会发展和科技进步,人类对新型硬质材料的需求也与日俱增。过渡金属氮化物由于普遍具有较高的硬度、耐磨性和耐腐蚀性以及高温化学稳定性被广泛应用于制作切割工具、耐磨涂层等,一直是材料领域的研究热点。通过第一性原理计算的方法研究大压力范围内材料结构和物性的变化,对指导实验有着重要的意义。本文基于第一性原理计算,采用结构搜索软件CALYPSO,对第VB族过渡金属一氮化物,二氮化物以及三元一氮化物进行大压力范围的结构探索,并对可能存在的结构进行稳定性验证和系统力学性质研究,以期对未来实验合成提供指导,在研究过程中获得了以下创新性结果:第一,对于V,Nb,Ta的二元一氮化物的研究表明,P-6m2结构为VN和Nb N的基态相,是在0 GPa到100 GPa范围内的最稳定结构,而Ta N的基态相为P-62m结构。他们的B1结构作为高温相在0 K、0压力下是不稳定的。通过与九个邻族一氮化物的对比研究得出,单位化学式中的价电子数VEC是影响一氮化物力学性质的关键因素,VN和Ta N由于具有最佳的VEC值是力学性质最好的一氮化物。弹性各向异性和强度各向异性计算表明P-6m2结构的力学各向异性要远小于B1结构。基于弹性模量的维氏硬度经验公式计算结果和理想强度计算表明,P-6m2结构VN和Ta N的理论硬度约为30 GPa,电子结构分析表明,过渡金属和氮之间形成一种介于离子键和共价键之间兼有金属键的混合键,其中共价作用是较高硬度和强度的根源所在。第二,对于V,Nb,Ta的二元二氮化物的研究表明,VN2在不同的压力范围内分别有六方相结构空间群为P63/mmc,正交相结构空间群为Cmc21和四方相结构空间群为I4/mcm三种结构。Nb N2和Ta N2在低压和高压区的结构一致分别为正交相Amm2结构和四方相I4/mcm结构。我们对这些结构进行了热力学、动力学以及力学稳定性验证,结果表明它们在0 K、0压时都是稳定的。弹性各向异性和理想强度计算结果显示,六方相和正交相的弹性各向异性较大,四方相结构具有最小的弹性各向异性,而VN2的基态结构六方相则表现出较好的理想强度和最小的强度各向异性,通过跟传统硬质材料B1结构的VN相比,力学性质提升较大。第三,对三元氮化物V0.5Ta0.5N,V0.5Nb0.5N和Nb0.5Ta0.5N的研究表明,它们在不同的压力范围内分别有正交相结构空间群为Pmm2,Cmc21和空间群为Fm-3m的立方相结构。对这三种结构进行的热力学、动力学以及力学稳定性验证结果表明这些结构在0 K、0压时都是稳定的。通过HSE06杂化泛函方法计算的立方相V0.5Ta0.5N和V0.5Nb0.5N的能带结构存在明显带隙,进一步分析表明,带隙主要是因为原子半径不同导致晶格中原子占位的细微差异引起。弹性各向异性和理想强度计算结果显示,正交相具有较小的弹性各向异性,立方相结构弹性各向异性较大,由于两种正交相只有金属原子排序的差异,因此形成焓差异较小,在实验合成时可能存在竞争关系。正交相具有较好的理想强度和最小的强度各向异性,其中Cmc21结构V0.5Ta0.5N的压痕剪切强度和维氏硬度达到了30GPa,因此可以用作硬质工程材料。
Abstract
sui zhao she hui fa zhan he ke ji jin bu ,ren lei dui xin xing ying zhi cai liao de xu qiu ye yu ri ju zeng 。guo du jin shu dan hua wu you yu pu bian ju you jiao gao de ying du 、nai mo xing he nai fu shi xing yi ji gao wen hua xue wen ding xing bei an fan ying yong yu zhi zuo qie ge gong ju 、nai mo tu ceng deng ,yi zhi shi cai liao ling yu de yan jiu re dian 。tong guo di yi xing yuan li ji suan de fang fa yan jiu da ya li fan wei nei cai liao jie gou he wu xing de bian hua ,dui zhi dao shi yan you zhao chong yao de yi yi 。ben wen ji yu di yi xing yuan li ji suan ,cai yong jie gou sou suo ruan jian CALYPSO,dui di VBzu guo du jin shu yi dan hua wu ,er dan hua wu yi ji san yuan yi dan hua wu jin hang da ya li fan wei de jie gou tan suo ,bing dui ke neng cun zai de jie gou jin hang wen ding xing yan zheng he ji tong li xue xing zhi yan jiu ,yi ji dui wei lai shi yan ge cheng di gong zhi dao ,zai yan jiu guo cheng zhong huo de le yi xia chuang xin xing jie guo :di yi ,dui yu V,Nb,Tade er yuan yi dan hua wu de yan jiu biao ming ,P-6m2jie gou wei VNhe Nb Nde ji tai xiang ,shi zai 0 GPadao 100 GPafan wei nei de zui wen ding jie gou ,er Ta Nde ji tai xiang wei P-62mjie gou 。ta men de B1jie gou zuo wei gao wen xiang zai 0 K、0ya li xia shi bu wen ding de 。tong guo yu jiu ge lin zu yi dan hua wu de dui bi yan jiu de chu ,chan wei hua xue shi zhong de jia dian zi shu VECshi ying xiang yi dan hua wu li xue xing zhi de guan jian yin su ,VNhe Ta Nyou yu ju you zui jia de VECzhi shi li xue xing zhi zui hao de yi dan hua wu 。dan xing ge xiang yi xing he jiang du ge xiang yi xing ji suan biao ming P-6m2jie gou de li xue ge xiang yi xing yao yuan xiao yu B1jie gou 。ji yu dan xing mo liang de wei shi ying du jing yan gong shi ji suan jie guo he li xiang jiang du ji suan biao ming ,P-6m2jie gou VNhe Ta Nde li lun ying du yao wei 30 GPa,dian zi jie gou fen xi biao ming ,guo du jin shu he dan zhi jian xing cheng yi chong jie yu li zi jian he gong jia jian zhi jian jian you jin shu jian de hun ge jian ,ji zhong gong jia zuo yong shi jiao gao ying du he jiang du de gen yuan suo zai 。di er ,dui yu V,Nb,Tade er yuan er dan hua wu de yan jiu biao ming ,VN2zai bu tong de ya li fan wei nei fen bie you liu fang xiang jie gou kong jian qun wei P63/mmc,zheng jiao xiang jie gou kong jian qun wei Cmc21he si fang xiang jie gou kong jian qun wei I4/mcmsan chong jie gou 。Nb N2he Ta N2zai di ya he gao ya ou de jie gou yi zhi fen bie wei zheng jiao xiang Amm2jie gou he si fang xiang I4/mcmjie gou 。wo men dui zhe xie jie gou jin hang le re li xue 、dong li xue yi ji li xue wen ding xing yan zheng ,jie guo biao ming ta men zai 0 K、0ya shi dou shi wen ding de 。dan xing ge xiang yi xing he li xiang jiang du ji suan jie guo xian shi ,liu fang xiang he zheng jiao xiang de dan xing ge xiang yi xing jiao da ,si fang xiang jie gou ju you zui xiao de dan xing ge xiang yi xing ,er VN2de ji tai jie gou liu fang xiang ze biao xian chu jiao hao de li xiang jiang du he zui xiao de jiang du ge xiang yi xing ,tong guo gen chuan tong ying zhi cai liao B1jie gou de VNxiang bi ,li xue xing zhi di sheng jiao da 。di san ,dui san yuan dan hua wu V0.5Ta0.5N,V0.5Nb0.5Nhe Nb0.5Ta0.5Nde yan jiu biao ming ,ta men zai bu tong de ya li fan wei nei fen bie you zheng jiao xiang jie gou kong jian qun wei Pmm2,Cmc21he kong jian qun wei Fm-3mde li fang xiang jie gou 。dui zhe san chong jie gou jin hang de re li xue 、dong li xue yi ji li xue wen ding xing yan zheng jie guo biao ming zhe xie jie gou zai 0 K、0ya shi dou shi wen ding de 。tong guo HSE06za hua fan han fang fa ji suan de li fang xiang V0.5Ta0.5Nhe V0.5Nb0.5Nde neng dai jie gou cun zai ming xian dai xi ,jin yi bu fen xi biao ming ,dai xi zhu yao shi yin wei yuan zi ban jing bu tong dao zhi jing ge zhong yuan zi zhan wei de xi wei cha yi yin qi 。dan xing ge xiang yi xing he li xiang jiang du ji suan jie guo xian shi ,zheng jiao xiang ju you jiao xiao de dan xing ge xiang yi xing ,li fang xiang jie gou dan xing ge xiang yi xing jiao da ,you yu liang chong zheng jiao xiang zhi you jin shu yuan zi pai xu de cha yi ,yin ci xing cheng han cha yi jiao xiao ,zai shi yan ge cheng shi ke neng cun zai jing zheng guan ji 。zheng jiao xiang ju you jiao hao de li xiang jiang du he zui xiao de jiang du ge xiang yi xing ,ji zhong Cmc21jie gou V0.5Ta0.5Nde ya hen jian qie jiang du he wei shi ying du da dao le 30GPa,yin ci ke yi yong zuo ying zhi gong cheng cai liao 。
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论文详细介绍
论文作者分别是来自西北大学的陈磊，发表于刊物西北大学2019-10-08论文，是一篇关于氮化物论文,晶体结构论文,弹性性质论文,理想强度论文,电子结构论文,西北大学2019-10-08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，资料来自西北大学2019-10-08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。