Chen Chen, Wang Qing, Dong Chuang, Zhang Yu, Dong Honggang
Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), School of Materials Science and Engineering, Dalian University of Technology, Dalian, 116024, China.
Department of Basic Courses, Liaoning Institute of Science and Technology, Benxi, 117004, China.
Sci Rep. 2020 Dec 10;10(1):21621. doi: 10.1038/s41598-020-78690-8.
The present work investigated the composition evolution of the TMS series of Ni-base single crystal (SC) superalloys in light of the cluster formula approach systematically. The cluster formula of SC superalloys could be expressed with [Formula: see text], in which all the alloying elements were classified into three groups, Al series ([Formula: see text]), Cr series ([Formula: see text]), and Ni series ([Formula: see text]). It was found that the total atom number (Z) of the cluster formula units for TMS series of superalloys varies from Z ~ 17 to Z ~ 15.5, and then to Z ~ 16 with the alloy development from the 1st to the 6th generation, in which the superalloys with prominent creep resistance possess an ideal cluster formula of [Formula: see text] with Z = 16. Similar tendency of composition evolution also appears in the PWA and CMSX series of SC superalloys. Typical TMS series of superalloys with prominent creep properties generally exhibit a moderate lattice misfit of γ/γ' which could render alloys with appropriate particle size of cuboidal γ' precipitates to acquire a maximum strength increment by precipitation strengthening mechanism. More importantly, the relationship between the lattice misfit (δ) of γ/γ' and the creep rupture lifetime (t) of superalloys was then established, showing a linear correlation in the form of lgt-lg|δ| at both conditions of 900 °C/392 MPa and 1100 °C/137 MPa. Combined with the lattice misfit, the cluster formula approach would provide a new way to modify or optimize the compositions of Ni-base superalloys for further improvement of creep property.
本工作系统地依据簇式法研究了TMS系列镍基单晶（SC）高温合金的成分演变。SC高温合金的簇式可表示为[公式：见原文]，其中所有合金元素被分为三组，铝系（[公式：见原文]）、铬系（[公式：见原文]）和镍系（[公式：见原文]）。研究发现，随着合金从第一代发展到第六代，TMS系列高温合金簇式单元的总原子数（Z）从Z ~ 17变化到Z ~ 15.5，然后变为Z ~ 16，其中具有突出抗蠕变性能的高温合金具有理想的簇式[公式：见原文]，Z = 16。在PWA和CMSX系列SC高温合金中也出现了类似的成分演变趋势。具有突出蠕变性能的典型TMS系列高温合金通常表现出适中的γ/γ'晶格错配，这可使合金具有尺寸合适的立方γ'析出相，从而通过析出强化机制获得最大强度增量。更重要的是，随后建立了γ/γ'的晶格错配（δ）与高温合金蠕变断裂寿命（t）之间的关系，在900 °C/392 MPa和1100 °C/137 MPa两种条件下均呈现lgt-lg|δ|形式的线性相关。结合晶格错配，簇式法将为调整或优化镍基高温合金成分以进一步提高蠕变性能提供一种新方法。
