Presents an experimental research into the rooling contact fatigue life of GCr15 steel with Ti xN, Ti xN+Ag and Ti xN+DLC layers ion implanted using the plasma ion implantation technology on a ball rod style high spee...Presents an experimental research into the rooling contact fatigue life of GCr15 steel with Ti xN, Ti xN+Ag and Ti xN+DLC layers ion implanted using the plasma ion implantation technology on a ball rod style high speed contact fatigue tester, and concludes with test results that the fatigue life increases to varying degrees with Ti xN, Ti xN+Ag, and Ti xN+DLC layers implanted, and increases 1.8 times with Ti xN+Ag layer implanted, hairline cracks grow continuously into fatigue pits under the action of shear stress in the superficial layer of material, and ion implantation acts to prevent initiation of cracks and slow down propagation of cracks.展开更多
Very high cycle fatigue（VHCF） properties of a low temperature tempering bearing steel GCr15 with smooth and hole-defect specimens are studied by employing a rotary bending test machine with frequency of 52.5 Hz.Both...Very high cycle fatigue（VHCF） properties of a low temperature tempering bearing steel GCr15 with smooth and hole-defect specimens are studied by employing a rotary bending test machine with frequency of 52.5 Hz.Both smooth and hole-defect specimens break in VHCF regime with some difference in fatigue crack initiation.For smooth specimens,a fine granular area（FGA） is observed near the grain boundary in the fracture surface of the specimens broken after 10~7 cycles. But no FGA is observed in the hole-defect specimens broken in VHCF regime,and the VHCF crack does not initiate from the small hole at the surface as it does at low or high cycle fatigue regime. Internal stress is employed to explain the VHCF behavior of these two types of specimens.At last,an advanced dislocation model based on Tanaka and Mura model is proposed to illustrate the internal stress process and to predict fatigue crack initiation life with FGA observed in the fracture region.展开更多
文摘Presents an experimental research into the rooling contact fatigue life of GCr15 steel with Ti xN, Ti xN+Ag and Ti xN+DLC layers ion implanted using the plasma ion implantation technology on a ball rod style high speed contact fatigue tester, and concludes with test results that the fatigue life increases to varying degrees with Ti xN, Ti xN+Ag, and Ti xN+DLC layers implanted, and increases 1.8 times with Ti xN+Ag layer implanted, hairline cracks grow continuously into fatigue pits under the action of shear stress in the superficial layer of material, and ion implantation acts to prevent initiation of cracks and slow down propagation of cracks.
基金supported by the National Natural Science Foundation of China(11021262 and 11172304)the National Basic Research Program of China (2012CB937500)
文摘Very high cycle fatigue（VHCF） properties of a low temperature tempering bearing steel GCr15 with smooth and hole-defect specimens are studied by employing a rotary bending test machine with frequency of 52.5 Hz.Both smooth and hole-defect specimens break in VHCF regime with some difference in fatigue crack initiation.For smooth specimens,a fine granular area（FGA） is observed near the grain boundary in the fracture surface of the specimens broken after 10~7 cycles. But no FGA is observed in the hole-defect specimens broken in VHCF regime,and the VHCF crack does not initiate from the small hole at the surface as it does at low or high cycle fatigue regime. Internal stress is employed to explain the VHCF behavior of these two types of specimens.At last,an advanced dislocation model based on Tanaka and Mura model is proposed to illustrate the internal stress process and to predict fatigue crack initiation life with FGA observed in the fracture region.
