Influence of Ag and Co additions on glass-forming ability, thermal and mechanical properties of Cu–Zr–Al bulk metallic glasses
Influence of Ag and Co additions on glass-forming ability, thermal and mechanical properties of Cu–Zr–Al bulk metallic glasses
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DOI：
10.1016/j.msea.2016.06.081
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发表时间：
2016-09
期刊：
影响因子：
6.4
通讯作者：
B. Escher;U. Kühn;J. Eckert;C. Rentenberger;S. Pauly
中科院分区：
文献类型：
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作者：
B. Escher;U. Kühn;J. Eckert;C. Rentenberger;S. Pauly
在这项研究中，不同的Ag和Co含量对玻璃形成合金（Cu 0. 5Zr 0. 5）95−x− yAl 5AgxCoy（2≤x≤5和0≤y≤2）和Cu 47. 5 − yZr 47. 5Al 5Coy（0≤y≤2）的热稳定性、相形成和力学性能的影响分别进行了研究。Ag的加入通过提高过冷熔体的稳定性和同时降低B2 CuZr高温相的稳定性来提高合金的玻璃形成能力（GFA）。相反，CO具有相反的效果。它导致B2相的热稳定性增加，以及过冷熔体的稳定性降低，并因此降低合金的GFA。此外，在铸造过程中引入的氧稳定的一些合金中析出亚稳的大立方体相。在相形成和本发明合金的玻璃化倾向之间存在强烈的相互依赖性。这种相关性可以通过从相应的转变温度计算的K参数（Song等人，2011 [1]）来捕获。本发明的三元、四元和五元合金的塑性应变也反映了GFA：形成玻璃的倾向越高，塑性应变越小。一旦B2晶体在玻璃中析出，塑性显著增强。
In this study, the effect different amounts of Ag and Co have on thermal stability, phase formation and mechanical properties of the glass-forming alloys (Cu0.5Zr0.5)95−x−yAl5AgxCoy(2≤x≤5 and 0≤y≤2) and Cu47.5−yZr47.5Al5Coy(0≤y≤2) was investigated, respectively. The addition of Ag increases the glass-forming ability (GFA) of the alloys by enhancing the stability of the undercooled melt and by simultaneously reducing the stability of the B2 CuZr high-temperature phase. Co instead, has the opposite effect. It leads to an increased thermal stability of the B2 phase, as well as a decreased stability of the undercooled melt and, consequently, lowers the GFA of the alloys. Moreover, a metastable big cube phase precipitates in some alloys stabilized by oxygen, which is introduced during casting. There is a strong interdependence between the phase formation and the tendency of the present alloys to vitrify. This correlation can be captured by the K-parameter (Song et al. 2011 [1]) calculated from the respective transformation temperatures. The plastic strain of the present ternary, quaternary and quinary alloys reflects the GFA as well: the higher the tendency to form a glass, the smaller the plastic strain. Once B2 crystals precipitate in the glass, the plasticity is enhanced significantly.