本文主要研究内容
作者韩宇翔（2019）在《挤压Mg-Dy-Ni合金板材显微组织、力学及腐蚀性能的研究》一文中研究指出：镁合金高温强度低,耐蚀性差一直限制其发展和应用。长周期堆垛结构（LPSO）相因其独特的原子堆垛排列,具有优异的机械和物理性能。利用LPSO相增强镁基体可显著提高合金的高温力学性能,具有广阔的应用前景。但作为一种新兴的Mg/LPSO耐热镁合金,仍有许多关键的科学问题有待进一步解决。例如LPSO相的结构类型对合金高温力学性能的影响规律及增强机理还不清晰,LPSO相的结构类型对合金腐蚀性能的影响规律及腐蚀机理还有待进一步澄清。这些科学问题的解决为新型耐热镁合金的设计及发展奠定数据基础。因此,本文结合上述的两个科学问题,通过传统的热挤压工艺,制备出含有LPSO结构相的挤压Mg-Dy-Ni合金,系统地研究了合金在时效过程中组织演变规律。揭示了合金的组织与高温力学性能的关系,定量评价了其对合金高温屈服强度的贡献,阐明了合金中不同类型LPSO相的增强机理。在此基础上,研究了含不同结构类型LPSO相合金的腐蚀性能,探讨了含不同结构类型LPSO相合金的腐蚀行为及腐蚀机理。具体实验结果如下:挤压态Mg-Dy-Ni合金主要是由沿挤压方向分布的α-Mg相、Mg2Dy相、层片状18R-LPSO相和晶粒内部少量细小的条纹状14H-LPSO相组成。挤压合金经过250℃时效处理后,层片状18R-LPSO相逐渐转变为块状,块状18R-LPSO相的体积分数逐渐增高,同时合金的晶粒内部析出了大量的14H-LPSO相。此外,经长时间时效后,挤压合金的平均晶粒尺寸也有所增长。挤压合金经250℃时效后在54 h和108 h处出现了两个硬度峰值,分别为90 HV和91 HV,比挤压态合金（82 HV）提高了10%。第一个硬度峰值的出现主要是由于18R-LPSO相的形貌由层片状转变为块状,该相的出现增强了弥散强化效应。第二个时效峰的出现主要是由于晶粒内部析出的14H-LPSO相体积分数增大,提高了析出强化作用。拉伸试验结果表明:经过108 h时效的挤压合金在室温和300℃具有最高的拉伸屈服强度和最大抗拉强度。54 h时效的挤压合金在300℃具有最大的断裂延伸率。如此优异的拉伸性能主要归功于合金中晶粒细化、块状18R-LPSO相的弥散强化、层片状18R-LPSO相的载荷转移强化以及大量14H-LPSO相的析出强化。相比于挤压Mg-Dy-Zn和挤压Mg-Dy-Cu合金,挤压Mg-Dy-Ni合金中层片状18R-LPSO相体积分数较高且弥散分布于整个基体。经过失重法和极化曲线测得合金的腐蚀速率较高(5.28×10-3/cm2/h)且腐蚀电流较大(2.54e-3A),由阻抗谱显示合金的高频容抗弧半径较小,腐蚀后溶液中的电荷转移电阻仅为0.91Ω/cm2,因此合金耐蚀性较低。挤压Mg-Dy-Ni合金的腐蚀类型是以丝状腐蚀为主的整体腐蚀,腐蚀丝存在于α-Mg/18R-LPSO相界面处,其方向与挤压方向一致。合金腐蚀速率较高,一方面由于体积分数较多且弥散分布的18R-LPSO相促进了微电偶的生成,丝状腐蚀形貌进一步为腐蚀液的渗入提供通道;另一方面由于Ni本身的析氢过电位较低,使合金容易发生氢化,提高了合金的腐蚀速率。此外,较小的晶粒尺寸也促进了腐蚀速率的加快。合金的腐蚀产物为Mg（OH）2,这种疏松多孔的腐蚀产物难以阻挡腐蚀液渗入基体,反应释放的氢气造成了腐蚀产物的剥落,加速了合金的腐蚀。
Abstract
mei ge jin gao wen jiang du di ,nai shi xing cha yi zhi xian zhi ji fa zhan he ying yong 。chang zhou ji dui duo jie gou （LPSO）xiang yin ji du te de yuan zi dui duo pai lie ,ju you you yi de ji xie he wu li xing neng 。li yong LPSOxiang zeng jiang mei ji ti ke xian zhe di gao ge jin de gao wen li xue xing neng ,ju you an kuo de ying yong qian jing 。dan zuo wei yi chong xin xing de Mg/LPSOnai re mei ge jin ,reng you hu duo guan jian de ke xue wen ti you dai jin yi bu jie jue 。li ru LPSOxiang de jie gou lei xing dui ge jin gao wen li xue xing neng de ying xiang gui lv ji zeng jiang ji li hai bu qing xi ,LPSOxiang de jie gou lei xing dui ge jin fu shi xing neng de ying xiang gui lv ji fu shi ji li hai you dai jin yi bu cheng qing 。zhe xie ke xue wen ti de jie jue wei xin xing nai re mei ge jin de she ji ji fa zhan dian ding shu ju ji chu 。yin ci ,ben wen jie ge shang shu de liang ge ke xue wen ti ,tong guo chuan tong de re ji ya gong yi ,zhi bei chu han you LPSOjie gou xiang de ji ya Mg-Dy-Nige jin ,ji tong de yan jiu le ge jin zai shi xiao guo cheng zhong zu zhi yan bian gui lv 。jie shi le ge jin de zu zhi yu gao wen li xue xing neng de guan ji ,ding liang ping jia le ji dui ge jin gao wen qu fu jiang du de gong suo ,chan ming le ge jin zhong bu tong lei xing LPSOxiang de zeng jiang ji li 。zai ci ji chu shang ,yan jiu le han bu tong jie gou lei xing LPSOxiang ge jin de fu shi xing neng ,tan tao le han bu tong jie gou lei xing LPSOxiang ge jin de fu shi hang wei ji fu shi ji li 。ju ti shi yan jie guo ru xia :ji ya tai Mg-Dy-Nige jin zhu yao shi you yan ji ya fang xiang fen bu de α-Mgxiang 、Mg2Dyxiang 、ceng pian zhuang 18R-LPSOxiang he jing li nei bu shao liang xi xiao de tiao wen zhuang 14H-LPSOxiang zu cheng 。ji ya ge jin jing guo 250℃shi xiao chu li hou ,ceng pian zhuang 18R-LPSOxiang zhu jian zhuai bian wei kuai zhuang ,kuai zhuang 18R-LPSOxiang de ti ji fen shu zhu jian zeng gao ,tong shi ge jin de jing li nei bu xi chu le da liang de 14H-LPSOxiang 。ci wai ,jing chang shi jian shi xiao hou ,ji ya ge jin de ping jun jing li che cun ye you suo zeng chang 。ji ya ge jin jing 250℃shi xiao hou zai 54 hhe 108 hchu chu xian le liang ge ying du feng zhi ,fen bie wei 90 HVhe 91 HV,bi ji ya tai ge jin （82 HV）di gao le 10%。di yi ge ying du feng zhi de chu xian zhu yao shi you yu 18R-LPSOxiang de xing mao you ceng pian zhuang zhuai bian wei kuai zhuang ,gai xiang de chu xian zeng jiang le mi san jiang hua xiao ying 。di er ge shi xiao feng de chu xian zhu yao shi you yu jing li nei bu xi chu de 14H-LPSOxiang ti ji fen shu zeng da ,di gao le xi chu jiang hua zuo yong 。la shen shi yan jie guo biao ming :jing guo 108 hshi xiao de ji ya ge jin zai shi wen he 300℃ju you zui gao de la shen qu fu jiang du he zui da kang la jiang du 。54 hshi xiao de ji ya ge jin zai 300℃ju you zui da de duan lie yan shen lv 。ru ci you yi de la shen xing neng zhu yao gui gong yu ge jin zhong jing li xi hua 、kuai zhuang 18R-LPSOxiang de mi san jiang hua 、ceng pian zhuang 18R-LPSOxiang de zai he zhuai yi jiang hua yi ji da liang 14H-LPSOxiang de xi chu jiang hua 。xiang bi yu ji ya Mg-Dy-Znhe ji ya Mg-Dy-Cuge jin ,ji ya Mg-Dy-Nige jin zhong ceng pian zhuang 18R-LPSOxiang ti ji fen shu jiao gao ju mi san fen bu yu zheng ge ji ti 。jing guo shi chong fa he ji hua qu xian ce de ge jin de fu shi su lv jiao gao (5.28×10-3/cm2/h)ju fu shi dian liu jiao da (2.54e-3A),you zu kang pu xian shi ge jin de gao pin rong kang hu ban jing jiao xiao ,fu shi hou rong ye zhong de dian he zhuai yi dian zu jin wei 0.91Ω/cm2,yin ci ge jin nai shi xing jiao di 。ji ya Mg-Dy-Nige jin de fu shi lei xing shi yi si zhuang fu shi wei zhu de zheng ti fu shi ,fu shi si cun zai yu α-Mg/18R-LPSOxiang jie mian chu ,ji fang xiang yu ji ya fang xiang yi zhi 。ge jin fu shi su lv jiao gao ,yi fang mian you yu ti ji fen shu jiao duo ju mi san fen bu de 18R-LPSOxiang cu jin le wei dian ou de sheng cheng ,si zhuang fu shi xing mao jin yi bu wei fu shi ye de shen ru di gong tong dao ;ling yi fang mian you yu Niben shen de xi qing guo dian wei jiao di ,shi ge jin rong yi fa sheng qing hua ,di gao le ge jin de fu shi su lv 。ci wai ,jiao xiao de jing li che cun ye cu jin le fu shi su lv de jia kuai 。ge jin de fu shi chan wu wei Mg（OH）2,zhe chong shu song duo kong de fu shi chan wu nan yi zu dang fu shi ye shen ru ji ti ,fan ying shi fang de qing qi zao cheng le fu shi chan wu de bao la ,jia su le ge jin de fu shi 。
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论文作者分别是来自兰州理工大学的韩宇翔，发表于刊物兰州理工大学2019-07-18论文，是一篇关于挤压合金论文,显微组织论文,力学性能论文,腐蚀性能论文,兰州理工大学2019-07-18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，资料来自兰州理工大学2019-07-18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。
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