Influence of prior cyclic oxidation on high temperature low cycle fatigue life of bare and Pt-Al coated superalloy Rene®80  

预循环氧化对无涂层和有Pt-Al涂层的Rene®80高温合金的高温低循环疲劳寿命的影响

作　　者：Mohammad Mehdi Barjesteh Karim Zangeneh Madar Seyed Mehdi Abbasi Kourosh Shirvani 

机构地区：[1]Faculty of Materials and Manufacturing Technologies,Malek Ashtar University of Technology(MUT),Babaie street,Lavizan,15875-1774,Tehran,Iran [2]Department of Advanced Materials and New Energies,Iranian Research organization for Science and Technology(IROST),33535-111,Tehran,Iran

出　　处：《Journal of Central South University》2022年第1期43-59,共17页中南大学学报（英文版）

摘　　要：The prediction of fatigue life of metallic alloys is justly accepted as one of the most important phenomena in the field of metallurgical and mechanical engineering.At elevated temperatures,oxidation of the surfaces has an effective role in the fatigue strength and ductility of the alloys.In the present work,the effect of prior cyclic oxidation on the high temperature low cycle fatigue(HTLCF)properties of nickel-based superalloy Rene®80 has been assessed in the uncoated state and in the Pt-aluminide(Pt-Al)coated condition at 930℃.To apply cyclic oxidation,simulation of engine thermal exposure was carried out by exposing coated and uncoated fatigue specimens in the burner rig(120 cycles at 1100℃).The cyclic oxidation procedure led to a changing in the coating microstructure from the dual-phase(ξ-PtAl_(2)+β-(Ni,Pt)Al)to single phase(β-(Ni,Pt)Al).Results of HTLCF tests showed an improvement in the HTLCF life around 11.5%in the unexposed coated specimen(pre-cyclic oxidation)as compared to unexposed bare specimen,while this rise for exposed coated specimen(post-cyclic oxidation)was only 5%.Although a mixed mode fracture morphology(ductile and brittle)was observed on the fracture surfaces of failed specimens,the wider regions of brittle fracture belonged to exposed coated/uncoated ones.预测金属合金的疲劳寿命是冶金和机械工程领域中最重要的研究之一。在高温下,表面氧化对合金的疲劳强度和延展性有重要影响。本文研究了预循环氧化对无涂层和有Pt-Al涂层的镍基高温合金Rene®80在930℃时的高温低循环疲劳(HTLCF)性能的影响。将有涂层和无涂层的疲劳试样在燃烧器钻机中进行发动机热暴露模拟(1100℃,120次循环)。循环氧化过程中涂层的微观结构由双相(ξ-PtAl_(2)+β-(Ni、Pt)Al)转变为单相(β-(Ni、Pt)Al)。结果显示,与未暴露的无涂层试样相比,未暴露的涂层试样(预循环氧化)的HTLCF寿命延长了约11.5%,暴露涂层试样(后循环氧化)的仅延长了5%。虽然断裂试样的断口表现为混合模式断裂形态(延性和脆性),但暴露涂层/无涂层的试样断口大部分属于脆性断裂。

关 键 词：Rene®80 superalloy Pt-aluminide cyclic oxidation low cycle fatigue FRACTOGRAPHY 

分 类 号：TG174.4[金属学及工艺—金属表面处理] TG132.3[金属学及工艺—金属学]