Mechanical properties evaluation by nano indentation of creep-fatigued ferritic heat-resisting steel (12Cr-2W)
A creep-fatigue test was conducted for a ferritic heat-resisting steel that contained 12mass%chromium and 2mass% tungsten.The creep-fatigue fracture of 12Cr-2W(pipe) originated from prior austenite grain boundaries.Subgrains neighboring the prior austenite grain boundaries became coarse during creep-fatigue testing.Nano-indentation tests were performed on the coarse subgrains neighboring grain boundaries and fine subgrains inner grains.As the results, The nano-scale hardness of the coarse subgrains neighboring to prior γ boundaries decreased markedly more than that of fine subgrains by the creep-fatigue and a pop-in behavior (in the relationship between force and penetration depth) occurred at only the coarse subgrains.The pop-in behaviors indicate that the dislocation density in the coarse subgrains should be lower by the recovery or rearrangement of dislocation by the creep-fatigue process at high-temperature.Therefore local deformations were assisted in the coarse subgraions neighboring to grain boundaries and introduce the intergranular fractures.
ferritic chromium-tungsten steel tempered martensite subgrain grain boundary creep-fatigue nano-indentation
Nobuo Nagashima Masao Hayakawa Megumi Kimura
National Institute for Materials Science (NIMS), Materials Reliability Center 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan
国际会议
长沙
英文
8-11
2016-10-16（万方平台首次上网日期，不代表论文的发表时间）