Ti is regarded as one of the promising grain refiners in cast Al-Li-Cu alloys,but few research works have been done on its independent role.In this study,the effect of Ti on the microstructure evolution and mechanical...Ti is regarded as one of the promising grain refiners in cast Al-Li-Cu alloys,but few research works have been done on its independent role.In this study,the effect of Ti on the microstructure evolution and mechanical properties of cast Al-2Li-2Cu-0.5Mg base alloy was investigated.The results revealed that the grains can be prominently refined with the increase of Ti addition.After adding Ti,high density TiB_(2)-Al_(3)Ti composite particles with a low lattice misfit form as heterogeneous nucleation sites for the α-Al matrix.δ’(Al3Li) and T_(1)(Al_(2)CuLi) precipitates that provide enhanced strength are dominated in the alloys after T6 aging treatment.The average size of both δ’ and half-width of δ’-precipitation free zone(PFZ) decreases gradually with the increase of Ti content.This is because the higher binding energy between Ti atoms and vacancies limits the diffusion efficiency of Li atoms,and thus results in a higher ductility.Additionally,no nano-sized Al_(3)Ti or core-shell structure of Al_(3)(Li,Ti) particles are found.The tensile property test results indicate that the Al-2Li-2Cu-0.5Mg alloy achieves optimal properties after aging at 175 °C for 32 h when 0.15wt.% Ti is added.It exhibits a yield strength of 352±5 MPa,an ultimate tensile strength of 423±6 MPa,and an elongation of(3±0.4)%.These findings are expected to offer a reliable theoretical guidance for the industrial composition design of the Al-Li-Cu series cast alloys.展开更多
The effects of heat treatment and solidification cooling rate on the microstructure and mechanical properties of as cast Ti 15 3 alloy prepared by induction skull melting method were investigated. Results show that th...The effects of heat treatment and solidification cooling rate on the microstructure and mechanical properties of as cast Ti 15 3 alloy prepared by induction skull melting method were investigated. Results show that the microstructure of as cast Ti 15 3 alloy changes from the features of simplified and larger size of beta grains to finer grain size with increasing solidification cooling rate. After solution treatment and different ageing treatment, alpha phase precipitates in grains interior as well as in grain boundaries. Due to the modification of the precipitate phase, the tensile strength and elongation of the alloy are improved simultaneously. A good combination of the values of 1.406?GPa of σ b and 4.5% of δ was obtained, which will be satisfied the use of this kind of alloy in critical areas.展开更多
The bulk glassy Cu 60 Zr 30 Ti 10 alloy with a diameter up to 4 mm and a length of 70 mm containing nanocrystalline phase was successfully developed by using copper mold casting method. The temperature interval of the...The bulk glassy Cu 60 Zr 30 Ti 10 alloy with a diameter up to 4 mm and a length of 70 mm containing nanocrystalline phase was successfully developed by using copper mold casting method. The temperature interval of the supercooled liquid region before crystallization is above 37 K. The glass transition temperature ( T g) and the reduced glass transition temperature ( T g/ T l) of the cast bulk glassy Cu 60 Zr 30 Ti 10 alloy are 713 K and 0.62. The cast bulk glassy alloy, which has high glassy forming ability, shows expected mechanical properties. The elastic modulus, yield strength, fracture strength and elongation including elastic elongation are 114 GPa, 1 785 MPa, 2 150 MPa and 3.3% respectively in compressive deformation, and 112 GPa, 1 780 MPa, 2 000 MPa and 1.9% respectively in tensile deformation. High resolution transmission electron microscope (HRTEM) and nano beam electron diffraction (NBED) studies indicate that the cast metallic bulk glassy Cu 60 Zr 30 Ti 10 alloy consists of nanocrystals with a size of 4 nm embedded in glassy matrix. The nanoparticle is identified as CuZr and has point space group symmetry of pm3m and its lattice parameter is a =0.3 262 nm . The nanocrystalline phase grew up to 10 nm upon annealing at 430 ℃ for 10 min and caused the alloy brittle.展开更多
The preparation and some mechanical, thermal and magnetic properties of the as cast bulk composite Fe72B19.2Sin.sM4 （M=Nb, Mo） alloys obtained by suction casting are presented and discussed. The microstructrural res...The preparation and some mechanical, thermal and magnetic properties of the as cast bulk composite Fe72B19.2Sin.sM4 （M=Nb, Mo） alloys obtained by suction casting are presented and discussed. The microstructrural results showed the existence of a crystalline a-Fe（Si） phase embedded in a glassy matrix. The values of microhardness （/Iv） and yield strength （ay） for the Nb-containing alloy are exceptionally high, i.e. （12.65~0.3） GPa and （4.22~0.10） GPa, respectively. The saturation polarization values are found to be as high as 1.24 T for both composite ~11oys. It is thought that the interplay between the secondary crystalline phases and amorphous matrix could be responsible for the mechanical and magnetic behaviour of these alloys.展开更多
基金financially supported by the National Natural Science Foundation of China (Nos.51821001 and 51871148)。
文摘Ti is regarded as one of the promising grain refiners in cast Al-Li-Cu alloys,but few research works have been done on its independent role.In this study,the effect of Ti on the microstructure evolution and mechanical properties of cast Al-2Li-2Cu-0.5Mg base alloy was investigated.The results revealed that the grains can be prominently refined with the increase of Ti addition.After adding Ti,high density TiB_(2)-Al_(3)Ti composite particles with a low lattice misfit form as heterogeneous nucleation sites for the α-Al matrix.δ’(Al3Li) and T_(1)(Al_(2)CuLi) precipitates that provide enhanced strength are dominated in the alloys after T6 aging treatment.The average size of both δ’ and half-width of δ’-precipitation free zone(PFZ) decreases gradually with the increase of Ti content.This is because the higher binding energy between Ti atoms and vacancies limits the diffusion efficiency of Li atoms,and thus results in a higher ductility.Additionally,no nano-sized Al_(3)Ti or core-shell structure of Al_(3)(Li,Ti) particles are found.The tensile property test results indicate that the Al-2Li-2Cu-0.5Mg alloy achieves optimal properties after aging at 175 °C for 32 h when 0.15wt.% Ti is added.It exhibits a yield strength of 352±5 MPa,an ultimate tensile strength of 423±6 MPa,and an elongation of(3±0.4)%.These findings are expected to offer a reliable theoretical guidance for the industrial composition design of the Al-Li-Cu series cast alloys.
文摘The effects of heat treatment and solidification cooling rate on the microstructure and mechanical properties of as cast Ti 15 3 alloy prepared by induction skull melting method were investigated. Results show that the microstructure of as cast Ti 15 3 alloy changes from the features of simplified and larger size of beta grains to finer grain size with increasing solidification cooling rate. After solution treatment and different ageing treatment, alpha phase precipitates in grains interior as well as in grain boundaries. Due to the modification of the precipitate phase, the tensile strength and elongation of the alloy are improved simultaneously. A good combination of the values of 1.406?GPa of σ b and 4.5% of δ was obtained, which will be satisfied the use of this kind of alloy in critical areas.
文摘The bulk glassy Cu 60 Zr 30 Ti 10 alloy with a diameter up to 4 mm and a length of 70 mm containing nanocrystalline phase was successfully developed by using copper mold casting method. The temperature interval of the supercooled liquid region before crystallization is above 37 K. The glass transition temperature ( T g) and the reduced glass transition temperature ( T g/ T l) of the cast bulk glassy Cu 60 Zr 30 Ti 10 alloy are 713 K and 0.62. The cast bulk glassy alloy, which has high glassy forming ability, shows expected mechanical properties. The elastic modulus, yield strength, fracture strength and elongation including elastic elongation are 114 GPa, 1 785 MPa, 2 150 MPa and 3.3% respectively in compressive deformation, and 112 GPa, 1 780 MPa, 2 000 MPa and 1.9% respectively in tensile deformation. High resolution transmission electron microscope (HRTEM) and nano beam electron diffraction (NBED) studies indicate that the cast metallic bulk glassy Cu 60 Zr 30 Ti 10 alloy consists of nanocrystals with a size of 4 nm embedded in glassy matrix. The nanoparticle is identified as CuZr and has point space group symmetry of pm3m and its lattice parameter is a =0.3 262 nm . The nanocrystalline phase grew up to 10 nm upon annealing at 430 ℃ for 10 min and caused the alloy brittle.
文摘The preparation and some mechanical, thermal and magnetic properties of the as cast bulk composite Fe72B19.2Sin.sM4 （M=Nb, Mo） alloys obtained by suction casting are presented and discussed. The microstructrural results showed the existence of a crystalline a-Fe（Si） phase embedded in a glassy matrix. The values of microhardness （/Iv） and yield strength （ay） for the Nb-containing alloy are exceptionally high, i.e. （12.65~0.3） GPa and （4.22~0.10） GPa, respectively. The saturation polarization values are found to be as high as 1.24 T for both composite ~11oys. It is thought that the interplay between the secondary crystalline phases and amorphous matrix could be responsible for the mechanical and magnetic behaviour of these alloys.
基金Natural Science Foundation of Hebei Province(E2013208181)STD Foundation of Hebei Province(15214705D)National Key Basic Research Development Program of China("973"Program)(5131902)
