Taking a Ti−5Al−5Mo−5V−1Cr−1Fe alloy as exemplary case,the fatigue crack growth sensitivity and fracture features with various tailoredαphase morphologies were thoroughly investigated using fatigue crack growth rate(...Taking a Ti−5Al−5Mo−5V−1Cr−1Fe alloy as exemplary case,the fatigue crack growth sensitivity and fracture features with various tailoredαphase morphologies were thoroughly investigated using fatigue crack growth rate(FCGR)test,optical microscopy(OM)and scanning electron microscopy(SEM).The tailored microstructures by heat treatments include the fine and coarse secondaryαphase,as well as the widmanstatten and basket weave features.The sample with coarse secondaryαphase exhibits better comprehensive properties of good crack propagation resistance(with long Paris regime ranging from 15 to 60 MPa·m1/2),high yield strength(1113 MPa)and ultimate strength(1150 MPa),and good elongation(11.6%).The good crack propagation resistance can be attributed to crack deflection,long secondary crack,and tortuous crack path induced by coarse secondaryαphase.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
基金Project(U1867201)supported by the National Natural Science Foundation of ChinaProject supported by State Key Laboratory of Powder Metallurgy,Central South University,China。
文摘Taking a Ti−5Al−5Mo−5V−1Cr−1Fe alloy as exemplary case,the fatigue crack growth sensitivity and fracture features with various tailoredαphase morphologies were thoroughly investigated using fatigue crack growth rate(FCGR)test,optical microscopy(OM)and scanning electron microscopy(SEM).The tailored microstructures by heat treatments include the fine and coarse secondaryαphase,as well as the widmanstatten and basket weave features.The sample with coarse secondaryαphase exhibits better comprehensive properties of good crack propagation resistance(with long Paris regime ranging from 15 to 60 MPa·m1/2),high yield strength(1113 MPa)and ultimate strength(1150 MPa),and good elongation(11.6%).The good crack propagation resistance can be attributed to crack deflection,long secondary crack,and tortuous crack path induced by coarse secondaryαphase.
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.
