Ultrasonic Bending Fatigue and Fracture Characteristic of a Chromium Containing Iron-based Sintered Material
A chromium containing iron-based powder metallurgy material of Fe-1.65Ni-1.4Cu-1Cr-0.5Mo-0.6C was prepared by die-wall lubricated double-direction cold pressing.After sintering,the material has a density of 7.22 g·cm-3 with a tensile strength of 884 MPa and elongation of 2.9%.The microstructure is mainly composed of pearlite with some bainite and retained austenite.The ultrasonic bending fatigue performance and fracture characteristic under 105-108 cycles was studied.Results show that the material exhibits a continually falling S-N curve and there is no sign for the presence of conventional plateau.The fatigue fractures show multiple crack initiating sites.Stress concentration,pores and inclusions are the main factors to cause crack initiation.In crack propagation region,fatigue striation is the typical feature.At high stress,the fracture has a large number of small cleavage planes and dimples,while the fatigue striation only exists locally.At low stress,dimples decrease while fatigue striations increase and some of the striations are worn down due to repeated pressing and friction under low cyclic loading.In rapid fracture region,there are typical cleavage planes with river pattern and dimples.At low stress,the existing of many cleavage planes indicates that the fracture occurs mainly in a brittle mode.At high stress,the emerging of dimples illustrates the presence of plastic deformation during fracture.
Chromium containing materials Ultrasonic fatigue Bending fatigue Fracture
Ke Meiyuan Chen Lu Wen Liping Liang Jibiao Xiao Zhiyu
National Engineering Research Center of Near-net-shape Forming for Metallic Materials,South China Un National Engineering Research Center of Near-net-shape Forming for Metallic Materials,South China Un Guangdong NBTM New Materials Co.,Ltd.,Jiangmen 529000,China
国际会议
北京
英文
502-508
2018-09-16（万方平台首次上网日期，不代表论文的发表时间）