Ultra-fine grained TA5 titanium alloy was fabricated by friction stir processing(FSP).Temperature distribution and material flow were simulated by the coupled Euler−Lagrange(CEL)method.The microstructure and mechanica...Ultra-fine grained TA5 titanium alloy was fabricated by friction stir processing(FSP).Temperature distribution and material flow were simulated by the coupled Euler−Lagrange(CEL)method.The microstructure and mechanical properties of TA5 alloy were characterized by optical and scanning electron microscope,Vickers hardness,and tensile tests.The processed alloy was composed of ultra-fine grained and equiaxed grains due to dynamic recrystallization.The microstructure recrystallized through grain boundary rotation and dislocation accumulation.The grain size reached the minimum on the advancing side of the stir zone with the highest grain misorientation.Ultimate tensile strength was promoted to over 830 MPa after FSP at a rotating speed of 200 r/min,whereas elongation varied a little.The specimens all fractured on the retreating side of the stir zone and smaller dimples were depicted from the fracture morphologies of FSP specimens.展开更多
The effect of geosynthetic reinforcing on bearing capacity of a strip footing resting on georeinforced clayey slopes was investigated.The results of a series of numerical study using finite element analyses on strip f...The effect of geosynthetic reinforcing on bearing capacity of a strip footing resting on georeinforced clayey slopes was investigated.The results of a series of numerical study using finite element analyses on strip footing upon both reinforced and unreinforced clayey slopes were presented.The objectives of this work are to:1) determine the influence of reinforcement on the bearing-capacity of the strip footings adjacent slopes,2) suggest an optimum number of reinforcement and 3) survey the effect of friction angle in clayey soils reinforced by geogrids.The investigations were carried out by varying the edge distance of the footing from slope.Also different numbers of geosynthetic layers were applied to obtaining the maximum bearing capacity and minimum settlement.To achieve the third objective,two different friction angles were used.The results show that the load?settlement behavior and ultimate bearing capacity of footing can be considerably improved by the inclusion of reinforcing layer.But using more than one layer reinforcement,the ultimate bearing capacity does not change considerably.It is also shown that for both reinforced and unreinforced slopes,the bearing capacity increases with an increase in edge distance.In addition,as the soil friction angle is increased,the efficiency of reinforcing reduces.展开更多
基金The authors are grateful for the financial support from the National Natural Science Foundation of China(51974100).
文摘Ultra-fine grained TA5 titanium alloy was fabricated by friction stir processing(FSP).Temperature distribution and material flow were simulated by the coupled Euler−Lagrange(CEL)method.The microstructure and mechanical properties of TA5 alloy were characterized by optical and scanning electron microscope,Vickers hardness,and tensile tests.The processed alloy was composed of ultra-fine grained and equiaxed grains due to dynamic recrystallization.The microstructure recrystallized through grain boundary rotation and dislocation accumulation.The grain size reached the minimum on the advancing side of the stir zone with the highest grain misorientation.Ultimate tensile strength was promoted to over 830 MPa after FSP at a rotating speed of 200 r/min,whereas elongation varied a little.The specimens all fractured on the retreating side of the stir zone and smaller dimples were depicted from the fracture morphologies of FSP specimens.
文摘The effect of geosynthetic reinforcing on bearing capacity of a strip footing resting on georeinforced clayey slopes was investigated.The results of a series of numerical study using finite element analyses on strip footing upon both reinforced and unreinforced clayey slopes were presented.The objectives of this work are to:1) determine the influence of reinforcement on the bearing-capacity of the strip footings adjacent slopes,2) suggest an optimum number of reinforcement and 3) survey the effect of friction angle in clayey soils reinforced by geogrids.The investigations were carried out by varying the edge distance of the footing from slope.Also different numbers of geosynthetic layers were applied to obtaining the maximum bearing capacity and minimum settlement.To achieve the third objective,two different friction angles were used.The results show that the load?settlement behavior and ultimate bearing capacity of footing can be considerably improved by the inclusion of reinforcing layer.But using more than one layer reinforcement,the ultimate bearing capacity does not change considerably.It is also shown that for both reinforced and unreinforced slopes,the bearing capacity increases with an increase in edge distance.In addition,as the soil friction angle is increased,the efficiency of reinforcing reduces.
