The crystal structure of[Cu(2-thienoyl-trifluoroacetone)(4,4—bipyridine)];was determined by X-ray diffraction analysis. The crystal belongs to monoclinie with the space group C2/c, Mr=440.91, a=9.640(5) A, b=24.9...The crystal structure of[Cu(2-thienoyl-trifluoroacetone)(4,4—bipyridine)];was determined by X-ray diffraction analysis. The crystal belongs to monoclinie with the space group C2/c, Mr=440.91, a=9.640(5) A, b=24.97(1) A, c=16.032(7) A, β=106.76(3)°,V=3695(3) A;, Z=8, Dc=1.58g/cm;, F(000)=1776. Final R and Rw are 0.062 and 0.069, respectively. The local coordination geometry around Cu(I) ion is a distorted tetrahedron. Cu(TTA) are linked with 4,4-bipyridine, forming long chain in the crystal.展开更多
Replacement of damaged long bones is still a significant challenge in surgery. In the present study, a NiTi Shape Memory Alloy (SMA) constructed with graded porosity imitating human long bone structure was fabricate...Replacement of damaged long bones is still a significant challenge in surgery. In the present study, a NiTi Shape Memory Alloy (SMA) constructed with graded porosity imitating human long bone structure was fabricated via a dedicated moulding procedure. The outer layer (porosity 14 %) and inner layer (porosity 52 %) of the bone-like graded NiTi alloy were found to be co-axial very well with the interface with a good metallurgical bonding. Moreover, the compression strength and elastic modulus of the graded-porosity NiTi SMAs were found to be 360.6 MPa and 6.7 GPa, respectively, which have been improved by its coaxiality compared with the one with poor coaxiality. The graded-porosity NiTi SMAs exhibit resembling mechanical performance as human long-bones, and are considered to be better implant candidates for long bone replacement.展开更多
The Mg96Y3Zn1 alloy processed by extrusion and equal channel angular pressing (ECAP) was investigated. It was found that the Mg96Y3Zn1 alloy processed by extrusion and ECAP obtained ultrafine grains and exhibited ex...The Mg96Y3Zn1 alloy processed by extrusion and equal channel angular pressing (ECAP) was investigated. It was found that the Mg96Y3Zn1 alloy processed by extrusion and ECAP obtained ultrafine grains and exhibited excellent mechanical properties. After ECAP, the average grain size of Mg96Y3Zn1 alloy was refined to about 400 nm. The highest strengths with yield strength of 381.45 MPa and ultimate tensile strength of 438.33 MPa were obtained after 2 passes at 623 K. The high strength of Mg96Y3Zn1 alloy was due to the strengthening by the grain refinement, the long period stacking (LPS) structure, solid solution, fine Mg24Y5 particles, and nano-scale precipitates. It was found that the elongation was decreased with pass number increasing. It was because that the cracks were preferentially initiated and propagated in the interior of X-phase during the tensile test.展开更多
Microstructures and precipitation behaviours of Mg94Y4Zn2 (at. %) extruded alloy during solution treatment and ageing processes were investigated. Three major phases were observed in the as-cast Ug94Zn2Y4 alloy:α-...Microstructures and precipitation behaviours of Mg94Y4Zn2 (at. %) extruded alloy during solution treatment and ageing processes were investigated. Three major phases were observed in the as-cast Ug94Zn2Y4 alloy:α-Mg, block shaped 1 8R long period stacking ordered (LPSO) phase and Mg24Y5 cuboid particles. After homogenization and extrusion, the block shaped LPSO phase changed into plate-like shape aligned along the direction of extrusion. During solution treatment, a small fraction of LPSO phase was transformed from 18R structure to 14H type. The nano-scale β' phase with its close-packed planes being perpendicular to the direction of both α-Mg and LPSO structure was precipitated at ageing stage. The coexistence of β' and LPSO phase contributes to the strengthening of the alloy, with microhardness for the matrix and LPSO structures reaching 145.8 and 155,0 HV, respectively.展开更多
文摘The crystal structure of[Cu(2-thienoyl-trifluoroacetone)(4,4—bipyridine)];was determined by X-ray diffraction analysis. The crystal belongs to monoclinie with the space group C2/c, Mr=440.91, a=9.640(5) A, b=24.97(1) A, c=16.032(7) A, β=106.76(3)°,V=3695(3) A;, Z=8, Dc=1.58g/cm;, F(000)=1776. Final R and Rw are 0.062 and 0.069, respectively. The local coordination geometry around Cu(I) ion is a distorted tetrahedron. Cu(TTA) are linked with 4,4-bipyridine, forming long chain in the crystal.
文摘Replacement of damaged long bones is still a significant challenge in surgery. In the present study, a NiTi Shape Memory Alloy (SMA) constructed with graded porosity imitating human long bone structure was fabricated via a dedicated moulding procedure. The outer layer (porosity 14 %) and inner layer (porosity 52 %) of the bone-like graded NiTi alloy were found to be co-axial very well with the interface with a good metallurgical bonding. Moreover, the compression strength and elastic modulus of the graded-porosity NiTi SMAs were found to be 360.6 MPa and 6.7 GPa, respectively, which have been improved by its coaxiality compared with the one with poor coaxiality. The graded-porosity NiTi SMAs exhibit resembling mechanical performance as human long-bones, and are considered to be better implant candidates for long bone replacement.
基金Project supported by the National Natural Science Foundation of China (51001072)
文摘The Mg96Y3Zn1 alloy processed by extrusion and equal channel angular pressing (ECAP) was investigated. It was found that the Mg96Y3Zn1 alloy processed by extrusion and ECAP obtained ultrafine grains and exhibited excellent mechanical properties. After ECAP, the average grain size of Mg96Y3Zn1 alloy was refined to about 400 nm. The highest strengths with yield strength of 381.45 MPa and ultimate tensile strength of 438.33 MPa were obtained after 2 passes at 623 K. The high strength of Mg96Y3Zn1 alloy was due to the strengthening by the grain refinement, the long period stacking (LPS) structure, solid solution, fine Mg24Y5 particles, and nano-scale precipitates. It was found that the elongation was decreased with pass number increasing. It was because that the cracks were preferentially initiated and propagated in the interior of X-phase during the tensile test.
基金the financial support of the project from the Natural Science Foundation of Jiangsu Province of China(No.BK2010392)the Innovation Foundation of Southeast University(No.3212000502)the Opening Project of Jiangsu Key Laboratory of Advanced Materials
文摘Microstructures and precipitation behaviours of Mg94Y4Zn2 (at. %) extruded alloy during solution treatment and ageing processes were investigated. Three major phases were observed in the as-cast Ug94Zn2Y4 alloy:α-Mg, block shaped 1 8R long period stacking ordered (LPSO) phase and Mg24Y5 cuboid particles. After homogenization and extrusion, the block shaped LPSO phase changed into plate-like shape aligned along the direction of extrusion. During solution treatment, a small fraction of LPSO phase was transformed from 18R structure to 14H type. The nano-scale β' phase with its close-packed planes being perpendicular to the direction of both α-Mg and LPSO structure was precipitated at ageing stage. The coexistence of β' and LPSO phase contributes to the strengthening of the alloy, with microhardness for the matrix and LPSO structures reaching 145.8 and 155,0 HV, respectively.