CHEN Lifan BA Tu SHI Changxu State Key Laboratory for Fatigue and Fracture of Materials
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Institute of Metal Research
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Academia Sinica
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Shenyang
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China Doctorate Student.Institute of Physics.Academia Sinica
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Beijing 100080
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China
金属学报(英文版)
50 keV B~+ ions was implanted to polycrvstalline with 50 keV B~+ to a dose o/ 3x 10~17 ions/cm~2 at room temperature.The specimens with and without B~+implantation were tested in micro-hardness and load or unload tensile fatigue under stress-controlled eondition. The surface layer structure was observed with IMA,SEM and TEM before and after implantation and/or fatigue.The B~+ implanted surface region consists of amorphous Ni-B phase,Ni_3B and Ni_4B_3 second phases,and damage structure.The corresponding measurements indicate that both surface micro-hardness and endurance limit of the specimens have increased after implantation.Compared with unimplanted specimens under the same fa- tigue condition,all implanted specimens show the smallest overall fatigue danage.The cyclic loading at room temperature can lead to migration of implanted B~+ out surface layer and reerystallization of amorphous Ni-B phase,Possible strengthening mechanisms.for these ex- perimental results were discussed.
关键词:
ion implantation
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