Sn对Zr基非晶内生复合材料微观组织与性能影响研究
发布时间：2018-11-07 12:41
【摘要】：与传统材料相比,块体金属玻璃(BMG)具有强度高、硬度大的优点,但特殊的原子结构同样也导致了其具有室温脆性这一严重缺陷,阻碍了 BMG在工程上的应用。因此,寻找提高BMG塑性的途径一直是非晶合金研究的热点问题。本文针对BMG发展中的问题,以微合金化和半固态保温热处理为主要手段开展以下研究:1)选择了一种Zr_56.2Ti_13.8Nb5.OCu_6.9Ni_5.6Be_12.5(S1)体系非晶合金为研究对象,其微观组织是BMG基体与析出体心立方结构的β-Zr树枝晶的内生相复合的典型组织,强度高的同时具有良好的塑性。为实现组织均匀化这个目标,采用了微合金化(Sn元素掺杂)的手段,通过 Bridgeman 方法制备了(Zr_56.2Ti_13.8Nb5.0Cu6.9Ni_5.6Be_12.5)1-xSnx(x=0,0.01,0.02)非晶合金试样,表征其微观组织演变规律,并进行了室温压缩试验,发现元素Sn的添加形成了 Zr5Sn3,可以作为β-相的异质形核核心,以此实现组织均匀细化。力学性能也明显提高,抗压强度达到1830MPa,比S1提高了200MPa。2)针对内生相对BMG复合材料力学性能的影响这个问题,和微合金化在均匀组织析出的过程中过于细化这一现象,分析了树枝晶的球化机理,采用半固态保温顺序凝固的手段制备了(Zr_56.2Ti_13.8Nb5.0Cu6.9Ni_5.6Be_12.5)1-x~Sn_x 球晶/BMG 复合材料,表征其显微组织的演变规律,进行室温压缩试验,探索了保温时间和Sn元素添加量的双重因素的影响。结果表明二者相互影响,当添加1at%.Sn的非晶合金复合材料保温30min时,得到的球晶尺寸最大,此时力学性能优异,塑性应变达到26%的同时,抗压强度仍有1530MPa。
[Abstract]:Compared with traditional materials, bulk metal glass (BMG) has the advantages of high strength and high hardness, but the special atomic structure also leads to its serious defect of room temperature brittleness, which hinders the application of BMG in engineering. Therefore, to find ways to improve the ductility of BMG has always been a hot issue in the study of amorphous alloys. This paper aims at the problems in the development of BMG, The main research methods are as follows: 1) A Zr_56.2Ti_13.8Nb5.OCu_6.9Ni_5.6Be_12.5 (S1) amorphous alloy is selected as the research object. The microstructure is a typical composite of BMG matrix and 尾-Zr dendrite, which has high strength and good plasticity. In order to achieve the goal of microstructure homogenization, microalloying (Sn element doping) was used. The samples of (Zr_56.2Ti_13.8Nb5.0Cu6.9Ni_5.6Be_12.5) 1-xSnx (x0. 01 ~ 0. 02) amorphous alloy were prepared by Bridgeman method, and their microstructure evolution was characterized, and the compression test at room temperature was carried out. It was found that the addition of element Sn formed Zr5Sn3, as the core of 尾-phase heterogeneous nucleation, so as to achieve uniform refinement of the structure. The mechanical properties of BMG composites were also significantly improved, the compressive strength reached 1830MPa, which was higher than S1 (200MPa.2). In view of the problem of the influence of endogenous mechanical properties on the mechanical properties of BMG composites, and the phenomenon that microalloying was too fine in the process of homogeneous microstructure precipitation, The spheroidization mechanism of dendrite was analyzed, and (Zr_56.2Ti_13.8Nb5.0Cu6.9Ni_5.6Be_12.5) 1-x~Sn_x spherulite / BMG composites were prepared by sequential solidification of semisolid heat preservation. The evolution rule of microstructure was characterized and the double factors of holding time and adding amount of Sn elements were explored by the compression test at room temperature. The results show that the spherulite size of amorphous alloy composite with 1at%.Sn is the largest, the mechanical properties are excellent, the plastic strain is 26%, and the compressive strength is 1530MPa.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG139.8
本文编号：2316407
[Abstract]:Compared with traditional materials, bulk metal glass (BMG) has the advantages of high strength and high hardness, but the special atomic structure also leads to its serious defect of room temperature brittleness, which hinders the application of BMG in engineering. Therefore, to find ways to improve the ductility of BMG has always been a hot issue in the study of amorphous alloys. This paper aims at the problems in the development of BMG, The main research methods are as follows: 1) A Zr_56.2Ti_13.8Nb5.OCu_6.9Ni_5.6Be_12.5 (S1) amorphous alloy is selected as the research object. The microstructure is a typical composite of BMG matrix and 尾-Zr dendrite, which has high strength and good plasticity. In order to achieve the goal of microstructure homogenization, microalloying (Sn element doping) was used. The samples of (Zr_56.2Ti_13.8Nb5.0Cu6.9Ni_5.6Be_12.5) 1-xSnx (x0. 01 ~ 0. 02) amorphous alloy were prepared by Bridgeman method, and their microstructure evolution was characterized, and the compression test at room temperature was carried out. It was found that the addition of element Sn formed Zr5Sn3, as the core of 尾-phase heterogeneous nucleation, so as to achieve uniform refinement of the structure. The mechanical properties of BMG composites were also significantly improved, the compressive strength reached 1830MPa, which was higher than S1 (200MPa.2). In view of the problem of the influence of endogenous mechanical properties on the mechanical properties of BMG composites, and the phenomenon that microalloying was too fine in the process of homogeneous microstructure precipitation, The spheroidization mechanism of dendrite was analyzed, and (Zr_56.2Ti_13.8Nb5.0Cu6.9Ni_5.6Be_12.5) 1-x~Sn_x spherulite / BMG composites were prepared by sequential solidification of semisolid heat preservation. The evolution rule of microstructure was characterized and the double factors of holding time and adding amount of Sn elements were explored by the compression test at room temperature. The results show that the spherulite size of amorphous alloy composite with 1at%.Sn is the largest, the mechanical properties are excellent, the plastic strain is 26%, and the compressive strength is 1530MPa.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG139.8
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