The influences of heat treatment on stress corrosion cracking （SCC）, fracture toughness and strength of 7085 aluminum alloy were investigated by slow strain rate testing, Kahn tear testing combined with scanning ele...The influences of heat treatment on stress corrosion cracking （SCC）, fracture toughness and strength of 7085 aluminum alloy were investigated by slow strain rate testing, Kahn tear testing combined with scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. The results show that the fracture toughness of T74 overaging is increased by 22.9% at the expense of 13.6% strength, and retrogression and reaging （RRA） enhances fracture toughness 14.2% without reducing the strength compared with T6 temper. The fracture toughness of dual-retrogression and reaging （DRRA） is equivalent to that of T74 with an increased strength of 14.6%. The SCC resistance increases in the order： T6〈RRA〈DRRA≈T74. The differences of fracture toughness and SCC were explained on the basis of the role of matrix precipitates and grain boundary orecioitates.展开更多
The occurrence of fractures in the vessel wall has been a major problem for human blood vessel cryopreservation. The large volumetric expansion of water during crystallization produces great inner stresses. To solve t...The occurrence of fractures in the vessel wall has been a major problem for human blood vessel cryopreservation. The large volumetric expansion of water during crystallization produces great inner stresses. To solve these complicated heat transfer and thermal stress problems, a model and an analytic method are presented in this paper, with which transient temperature field, the transient stress field inside the blood vessels during freezing can be calculated and analyzed, and the probable cracks or fractures can be predicted. The analytic results of sheep thoracic artery are consistent with the experimental observations of fractures.展开更多
This paper studies the thermoelastic fracture in a solid under non-classical Fourier heat conduction.The temperature field and the associated thermal stresses are solved by the dual integral equation technique.Both th...This paper studies the thermoelastic fracture in a solid under non-classical Fourier heat conduction.The temperature field and the associated thermal stresses are solved by the dual integral equation technique.Both thermally insulated crack and heated crack are considered.It is found that the crack tip thermal stress is singular and can be expressed in terms of the thermal stress intensity factor in a closed-form.Numerical results show that the crack considerably amplifies the local thermal stresses,confirming the significance of the effect of non-classical heat conduction on the thermoelastic fracture mechanics of materials.展开更多
基金Projects(2010CB731701,2012CB619502)supported by the National Basic Research Program of ChinaProjects(51201186,51327902)supported by the National Natural Science Foundation of China
文摘The influences of heat treatment on stress corrosion cracking （SCC）, fracture toughness and strength of 7085 aluminum alloy were investigated by slow strain rate testing, Kahn tear testing combined with scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. The results show that the fracture toughness of T74 overaging is increased by 22.9% at the expense of 13.6% strength, and retrogression and reaging （RRA） enhances fracture toughness 14.2% without reducing the strength compared with T6 temper. The fracture toughness of dual-retrogression and reaging （DRRA） is equivalent to that of T74 with an increased strength of 14.6%. The SCC resistance increases in the order： T6〈RRA〈DRRA≈T74. The differences of fracture toughness and SCC were explained on the basis of the role of matrix precipitates and grain boundary orecioitates.
文摘The occurrence of fractures in the vessel wall has been a major problem for human blood vessel cryopreservation. The large volumetric expansion of water during crystallization produces great inner stresses. To solve these complicated heat transfer and thermal stress problems, a model and an analytic method are presented in this paper, with which transient temperature field, the transient stress field inside the blood vessels during freezing can be calculated and analyzed, and the probable cracks or fractures can be predicted. The analytic results of sheep thoracic artery are consistent with the experimental observations of fractures.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10972067 and 11172081)
文摘This paper studies the thermoelastic fracture in a solid under non-classical Fourier heat conduction.The temperature field and the associated thermal stresses are solved by the dual integral equation technique.Both thermally insulated crack and heated crack are considered.It is found that the crack tip thermal stress is singular and can be expressed in terms of the thermal stress intensity factor in a closed-form.Numerical results show that the crack considerably amplifies the local thermal stresses,confirming the significance of the effect of non-classical heat conduction on the thermoelastic fracture mechanics of materials.
