【摘要】：與傳統(tǒng)材料相比,塊體金屬玻璃(BMG)具有強(qiáng)度高、硬度大的優(yōu)點(diǎn),但特殊的原子結(jié)構(gòu)同樣也導(dǎo)致了其具有室溫脆性這一嚴(yán)重缺陷,阻礙了 BMG在工程上的應(yīng)用。因此,尋找提高BMG塑性的途徑一直是非晶合金研究的熱點(diǎn)問(wèn)題。本文針對(duì)BMG發(fā)展中的問(wèn)題,以微合金化和半固態(tài)保溫?zé)崽幚頌橹饕侄伍_(kāi)展以下研究:1)選擇了一種Zr_56.2Ti_13.8Nb5.OCu_6.9Ni_5.6Be_12.5(S1)體系非晶合金為研究對(duì)象,其微觀組織是BMG基體與析出體心立方結(jié)構(gòu)的β-Zr樹(shù)枝晶的內(nèi)生相復(fù)合的典型組織,強(qiáng)度高的同時(shí)具有良好的塑性。為實(shí)現(xiàn)組織均勻化這個(gè)目標(biāo),采用了微合金化(Sn元素?fù)诫s)的手段,通過(guò) Bridgeman 方法制備了(Zr_56.2Ti_13.8Nb5.0Cu6.9Ni_5.6Be_12.5)1-xSnx(x=0,0.01,0.02)非晶合金試樣,表征其微觀組織演變規(guī)律,并進(jìn)行了室溫壓縮試驗(yàn),發(fā)現(xiàn)元素Sn的添加形成了 Zr5Sn3,可以作為β-相的異質(zhì)形核核心,以此實(shí)現(xiàn)組織均勻細(xì)化。力學(xué)性能也明顯提高,抗壓強(qiáng)度達(dá)到1830MPa,比S1提高了200MPa。2)針對(duì)內(nèi)生相對(duì)BMG復(fù)合材料力學(xué)性能的影響這個(gè)問(wèn)題,和微合金化在均勻組織析出的過(guò)程中過(guò)于細(xì)化這一現(xiàn)象,分析了樹(shù)枝晶的球化機(jī)理,采用半固態(tài)保溫順序凝固的手段制備了(Zr_56.2Ti_13.8Nb5.0Cu6.9Ni_5.6Be_12.5)1-x~Sn_x 球晶/BMG 復(fù)合材料,表征其顯微組織的演變規(guī)律,進(jìn)行室溫壓縮試驗(yàn),探索了保溫時(shí)間和Sn元素添加量的雙重因素的影響。結(jié)果表明二者相互影響,當(dāng)添加1at%.Sn的非晶合金復(fù)合材料保溫30min時(shí),得到的球晶尺寸最大,此時(shí)力學(xué)性能優(yōu)異,塑性應(yīng)變達(dá)到26%的同時(shí),抗壓強(qiáng)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.
【學(xué)位授予單位】：南京理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類(lèi)號(hào)】：TG139.8

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本文編號(hào)：2316407