以不同厂家生产的两炉18Cr Ni Mo7-6齿轮钢(标记为IQ-T-1、IQ-T-2)为研究对象,分析了试验钢经亚温淬火-回火(Intercritical quenching and tempering,IQ-T)处理后的显微组织对其力学性能、旋转弯曲疲劳性能和疲劳裂纹扩展行为的影响。...以不同厂家生产的两炉18Cr Ni Mo7-6齿轮钢(标记为IQ-T-1、IQ-T-2)为研究对象,分析了试验钢经亚温淬火-回火(Intercritical quenching and tempering,IQ-T)处理后的显微组织对其力学性能、旋转弯曲疲劳性能和疲劳裂纹扩展行为的影响。结果表明:IQ-T-1试验钢的强度和疲劳强度较IQ-T-2试验钢分别提高了97 MPa和96 MPa,具有更好的力学性能和疲劳性能。IQ-T-1试验钢组织为细小铁素体+小块马氏体+回火马氏体,而IQ-T-2试验钢组织为粗大铁素体+回火马氏体。IQ-T-1试验钢中细小铁素体+小块马氏体使裂纹分枝、裂纹闭合和应力屏蔽现象均更为显著,对裂纹萌生和扩展的阻碍作用更大。展开更多
Threshold of fatigue for short through cracks for Al-Li alloy 8090 was evaluated to be lower than that of long cracks,and to decrease with the shortening of the crack length.The correla- tion among the threshold,crack...Threshold of fatigue for short through cracks for Al-Li alloy 8090 was evaluated to be lower than that of long cracks,and to decrease with the shortening of the crack length.The correla- tion among the threshold,crack wake,and crack tip shielding of the short fatigue cracks was discussed.The super demarcation length and lowest theoretical threshold of short through fa- tigue cracks were presented.展开更多
The growth behavior of fatigue cracks for alurninum-lithium alloy 2090 and traditional aluminum alloy2024 was investisated. Specific einphasis was placed on explorins the correlation among crack closure effect,intrins...The growth behavior of fatigue cracks for alurninum-lithium alloy 2090 and traditional aluminum alloy2024 was investisated. Specific einphasis was placed on explorins the correlation among crack closure effect,intrinsic growth resistance and fractographic features. A comparing to alloy 7075 , alloy 2090 shows the excel-lent nominal growth resistance of fatigue cracks, inferior intrinsic growth resistance in the near-threshold zoneand superior one in the Ⅲ zone. The mechanism of extrinsic toughness effect in the near-threshold zone iscrack closure effect. The excellect norninal and intrinsic growth resistance of fatigue cracks in the Ⅲ zone is at-tributed to the delamination toughness effect. A certain level of crack closure effect and the near-delaminationtoughness effect ean be achieved in the Paris zone.展开更多
文摘以不同厂家生产的两炉18Cr Ni Mo7-6齿轮钢(标记为IQ-T-1、IQ-T-2)为研究对象,分析了试验钢经亚温淬火-回火(Intercritical quenching and tempering,IQ-T)处理后的显微组织对其力学性能、旋转弯曲疲劳性能和疲劳裂纹扩展行为的影响。结果表明:IQ-T-1试验钢的强度和疲劳强度较IQ-T-2试验钢分别提高了97 MPa和96 MPa,具有更好的力学性能和疲劳性能。IQ-T-1试验钢组织为细小铁素体+小块马氏体+回火马氏体,而IQ-T-2试验钢组织为粗大铁素体+回火马氏体。IQ-T-1试验钢中细小铁素体+小块马氏体使裂纹分枝、裂纹闭合和应力屏蔽现象均更为显著,对裂纹萌生和扩展的阻碍作用更大。
文摘Threshold of fatigue for short through cracks for Al-Li alloy 8090 was evaluated to be lower than that of long cracks,and to decrease with the shortening of the crack length.The correla- tion among the threshold,crack wake,and crack tip shielding of the short fatigue cracks was discussed.The super demarcation length and lowest theoretical threshold of short through fa- tigue cracks were presented.
文摘The growth behavior of fatigue cracks for alurninum-lithium alloy 2090 and traditional aluminum alloy2024 was investisated. Specific einphasis was placed on explorins the correlation among crack closure effect,intrinsic growth resistance and fractographic features. A comparing to alloy 7075 , alloy 2090 shows the excel-lent nominal growth resistance of fatigue cracks, inferior intrinsic growth resistance in the near-threshold zoneand superior one in the Ⅲ zone. The mechanism of extrinsic toughness effect in the near-threshold zone iscrack closure effect. The excellect norninal and intrinsic growth resistance of fatigue cracks in the Ⅲ zone is at-tributed to the delamination toughness effect. A certain level of crack closure effect and the near-delaminationtoughness effect ean be achieved in the Paris zone.