GH3535合金中晶界特征对碲致脆性开裂影响的分形分析  

Fractal Analysis of the Effect of Grain Boundary Character on Te-Induced Brittle Cracking in GH3535 Alloy

作　　者：杨杜 白琴[1] 胡悦 张勇 李志军[2] 蒋力[2] 夏爽[1] 周邦新[1] YANG Du;BAI Qin;HU Yue;ZHANG Yong;LI Zhijun;JIANG Li;XIA Shuang;ZHOU Bangxin(Institute of Materials,Shanghai University,Shanghai 200072,China;Shanghai Institute of Applied Physics,Chinese Academy of Sciences,Shanghai 201800,China)

机构地区：[1]上海大学材料研究所,上海200072 [2]中国科学院上海应用物理研究所,上海201800

出　　处：《金属学报》2023年第2期248-256,共9页Acta Metallurgica Sinica

基　　金：国家重点研发计划项目No.2018YFE0122100;国家自然科学基金项目No.51871144。

摘　　要：对GH3535合金进行晶界工程(GBE)处理,将得到的GBE样品与未经GBE处理(Non-GBE)样品在700℃下渗碲500 h,再进行原位三点弯曲实验,比较渗碲后GBE和Non-GBE样品的开裂性能,并对三点弯曲实验前局部区域的不同类型晶界取向成像显微图和三点弯曲实验后原位裂纹的形貌图进行分形分析。随机晶界(RGB)与裂纹的分形维数变化趋势相同,随机晶界的分形维数越小,材料抗开裂性能越好。GBE样品中因大尺寸孪晶晶粒团簇的平均尺寸更大,且分布更加均匀,有利于提高材料的抗开裂性能。GH3535 alloy has been used as the main structural material of molten salt reactor,which exhibits good high-temperature strength and excellent corrosion resistance to the molten salts.The intergranular cracking of GH3535 was detected after four years of operation of the molten salt reactor experiment,which was attributed to the inward diffusion of fission products Te.Grain boundary engineering(GBE)has been successfully applied to enhance the grain-boundary-related properties of the materials by increasing the frequency of lowΣcoincidence site lattice grain boundaries and tailoring the grain boundary network.The in situ three-point bending test was used to assess the cracking properties of NonGBE and GBE samples following Te infiltration at 700o C for 500 h.Fractal analysis statistics of various types of grain boundaries and cracks following in situ three-point bending tests were used.The result shows that the fractal dimension of cracks is in accord with that of the random grain boundaries(RGBs).The stronger the fracture resistance of materials,the lower the value of the RGB fractal dimension.The GH3535 alloy GBE samples with a bigger average size and more uniformly distributed twin grain clusters will have greater cracking resistance.

关 键 词：GH3535合金 晶界工程 三点弯曲 裂纹 分形维数 

分 类 号：TG174.1[金属学及工艺—金属表面处理]