Characterization of localized deformation near grain boundaries of superalloy Rene-104 at elevated temperature
Characterization of localized deformation near grain boundaries of superalloy Rene-104 at elevated temperature
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DOI：
10.1016/j.msea.2014.03.048
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发表时间：
2014-05-27
期刊：
影响因子：
6.4
通讯作者：
Mills, Michael J.
中科院分区：
文献类型：
--
作者：
Carter, Jennifer L. W.;Kuper, Michael W.;Mills, Michael J.
在700℃恒定载荷下，采用原位表面变形测量技术对镍基高温合金的应变局部化位点进行了表征。变形图与电子背散射衍射（EBSD）测量的晶粒位置和取向相结合，将局部化位点与下表层微观结构联系起来。对高温合金Rene-104进行热处理和淬火，形成两种晶粒尺寸相近但晶界特征不同的组织：标准组织为微观上的平面晶界，而标准组织为锯齿晶界。对原位扫描电镜（SEM）图像计算的全场应变图的分析表明，两种微观结构的应变局部化作为总应变的函数存在明显差异。标准组织的应变积累很少，退火孪晶界在应变局部化位点起重要作用，而锯齿状组织的应变积累在整个组织中更加均匀。两种显微组织均存在晶界滑动（GBS），但锯齿状晶界的发展显著降低了这一机制对整体应变调节的贡献，从20%降至14%。(C) 2014 Elsevier B.V.版权所有
in situ surface deformation measurement techniques were applied to characterize strain localization sites in nickel-based superalloys when tested under constant load at 700 degrees C. Deformation maps were coupled with electron backscatter diffraction (EBSD) measurement of grain location and orientation to correlate localization sites with underlying surface microstructure. Superalloy Rene-104 was heat treated and quenched to create two microstructures with similar grain sizes but different grain boundary character: the standard microstructure had microscopically planar grain boundaries, and the other microstructure had serrated grain boundaries. Analysis of full field strain maps calculated from in situ scanning electron microscopy (SEM) images indicated distinct differences in strain localization as a function of total strain for the two microstructures. The standard microstructure showed very little intra-granular strain accumulation, and annealing twin boundaries played an important role in strain localization sites, whereas the serrated microstructure experienced strain accumulation more evenly throughout the microstructure. Grain boundary sliding (GBS) was observed in both microstructures, but the development of serrated grain boundaries significantly decreased the contribution of this mechanism to the overall strain accommodation from 20% to 14% of the total plastic strain being accommodated by GBS. (C) 2014 Elsevier B.V. All rights reserved.