Curves of △Kth vs.△ath and △Kcl·th vs.△ath for aluminum-lithium alloy 2090 have been determined and compared with those for traditional aluminum alloy 2024.The growth resistance of short fatigue cracks for al...Curves of △Kth vs.△ath and △Kcl·th vs.△ath for aluminum-lithium alloy 2090 have been determined and compared with those for traditional aluminum alloy 2024.The growth resistance of short fatigue cracks for aluminum-lithium alloy 2090 is quantitatively evaluated.The essential reason resulting in stronger short cracks effect has been ascertained.Influence of cerium on the growth behavior of short fatigue cracks for aluminum-lithium alloy 2090 was investigated.The results show that by adding cerium into this alloy a significant improvement in △Ki can be achieved and at the same time △Kcl·th is increased.Consequently,the essential factor resulting in lower growth resistance of short fatigue cracks for this alloy is removed and the growth resistance of long and short fatigue cracks is increased.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Curves of △Kth vs.△ath and △Kcl·th vs.△ath for aluminum-lithium alloy 2090 have been determined and compared with those for traditional aluminum alloy 2024.The growth resistance of short fatigue cracks for aluminum-lithium alloy 2090 is quantitatively evaluated.The essential reason resulting in stronger short cracks effect has been ascertained.Influence of cerium on the growth behavior of short fatigue cracks for aluminum-lithium alloy 2090 was investigated.The results show that by adding cerium into this alloy a significant improvement in △Ki can be achieved and at the same time △Kcl·th is increased.Consequently,the essential factor resulting in lower growth resistance of short fatigue cracks for this alloy is removed and the growth resistance of long and short fatigue cracks is increased.
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.