With the sublattice model, equilibrium compositions of ferrite (a) and austenite (7 ) phases, as well as the volume percent of austenite (7) at 780℃ in different TRIP steels were calculated. Concentration profiles of...With the sublattice model, equilibrium compositions of ferrite (a) and austenite (7 ) phases, as well as the volume percent of austenite (7) at 780℃ in different TRIP steels were calculated. Concentration profiles of carbon, Mn, Al and Si in the steels were also estimated under the lattice fixed frame of reference so as to understand the complex mechanical behavior of TRIP steels after different isothermal bainitic transformation treatments. The effect of Si and Mn on transformation induced plasticity (TRIP) was discussed according to thermodynamic and kinetic analyses. It is recognized that Al also induces phase transformation in the steels but its TRIP effect is not as strong as that of Si.展开更多
Research status of high strength low alloy TRIP (transformation induced plasticity) steels for automobile structural parts is briefly described. Composition and microstruc-ture factors especially the morphology, size ...Research status of high strength low alloy TRIP (transformation induced plasticity) steels for automobile structural parts is briefly described. Composition and microstruc-ture factors especially the morphology, size and volume fraction of retained austenite, which largely influence the strength and ductility of the steel, are reviewed and discussed one after another. Modelling of the inter-critical annealing and martempering processes as well as the designing of the TRIP steel aided by commercial software are introduced. Some special aspects of the dynamic mechanical properties of TRIP steel are firstly reported.展开更多
The improvement of machining behavior of prehardened-mould steel for plastic is realized by using computer-aided composition design in this work. The results showed that the matrix composition of large sectional preha...The improvement of machining behavior of prehardened-mould steel for plastic is realized by using computer-aided composition design in this work. The results showed that the matrix composition of large sectional prehardened mould steel for plastic markedly influences the precipitation of non-metallic inclusion and the control of composition aided by Thermo-Calc software package minimizes the amount of detrimental oxide inclusion. In addition the modification of calcium is optimized in the light of composition design.展开更多
With the two sublattices model, equilibrium compositions of ferrite (α) and austenite (γ) phases, as well as the volume percent of austenite (γ) in different TRIP steels are calculated. Concentration profiles of ca...With the two sublattices model, equilibrium compositions of ferrite (α) and austenite (γ) phases, as well as the volume percent of austenite (γ) in different TRIP steels are calculated. Concentration profiles of carbon, manganese, aluminum and silicon in these steels are also estimated under the lattice fixed frame of reference so as to identify if the equilibrium state is obtained. Through the comparison between the profiles after different time diffusion, the distribution of elements in phases is exhibited and the complex effect due to the mutual interaction of the elements on diffusion is discussed.展开更多
MX 2 (M=Mo, W; X=S, Se) and DLC (a C: H and WC/C) are the two kinds of typical low friction coatings widely used in industry. The friction and wear properties of these two kinds of coatings marked as MOVIC, MOST, MoSe...MX 2 (M=Mo, W; X=S, Se) and DLC (a C: H and WC/C) are the two kinds of typical low friction coatings widely used in industry. The friction and wear properties of these two kinds of coatings marked as MOVIC, MOST, MoSe 2/Ni, WSe 2, a C: H and WC/C coatings were determined by fretting tests in ambient air of different humidity. The results show that the coefficient of friction of MX 2 coatings increases when the relative humidity of air increases whereas the coefficient of friction DLC coatings decreases with the increasing of relative humidity. MOVIC and WSe 2 coatings have a poor friction and wear resistance because of non basal planes (100) and (101) parallel to the surface in the MOVIC coating, or the rough and porous surface of WSe 2 coatings. Among these six coatings, MoSe 2/Ni and WC/C coatings have the highest wear resistance which seems to be unaffected by the relative humidity.展开更多
Suitable optimization and simulation were performed using a powerful software package with a mature database as well as modem measurement facilities, which led to the successful designing and manufacturing of advanced...Suitable optimization and simulation were performed using a powerful software package with a mature database as well as modem measurement facilities, which led to the successful designing and manufacturing of advanced steels. In the course of designing, the composition of a large section of prehardened mold steel for plastics was estimated so as to lower the quantities of oxide inclusions to change the type of carbides and to raise the machinability. The composition and process were adjusted to obtain satisfactory surface quality for the prevailing galvanization in transformation-induced plasticity （TRIP） steel. The refuting process of low-carbon steel was simulated in the light of both Thermo-Calc and Factsage. Thermodynamic and kinetic analyses were always conducted during the test and the procedure.展开更多
The application of substitutional model in oxide systems, in comparison with that of sublattice model, is discussed.The results show that in the case of crystalline phases and liquid phases without molecular-like asso...The application of substitutional model in oxide systems, in comparison with that of sublattice model, is discussed.The results show that in the case of crystalline phases and liquid phases without molecular-like associates or theshortage of element in sublattice, these two models get consistent in the description of the formalism of Gibbs freeenergies of phases and obtain the same result of phase diagram calculation when the valence of the cations keep thesame.展开更多
MoS coatings were prepared by means of bipolar-pulsed DC magnetron sputtering on different substrate type at various temperature. The structure and fretting behavior of MoS, coatings have been determined respectively ...MoS coatings were prepared by means of bipolar-pulsed DC magnetron sputtering on different substrate type at various temperature. The structure and fretting behavior of MoS, coatings have been determined respectively by XRD and fretting tester in air of 10% to 90% RH and under the load of 1 to 10 N. With increasing substrate temperature, the edge orientation evolves in the MoSx coating, and the relative content of edge-to-basal orientation becomes large. The tribological performance of coatings gets deteriorated. Compared with MoS, coatings on TiN/H13, CrN/H13 and MoS /Ti multilayer, MoS coating on H13 substrate has a lower load bearing capacity, and worn away easily under higher normal load 5N or ION and in air of 90% RH during the fretting process. The friction and wear properties of MoS, coatings on TiN/H13 and CrN/H13 (dual-layer) are slight better than that of MoS, /Ti multilayer under the normal load tested and in air of<10%to90%RH.展开更多
基金This work was financially supported by the National Natural Science Foundation of China(No.50171038)the China-Belgium bilateral project(2001-242).
文摘With the sublattice model, equilibrium compositions of ferrite (a) and austenite (7 ) phases, as well as the volume percent of austenite (7) at 780℃ in different TRIP steels were calculated. Concentration profiles of carbon, Mn, Al and Si in the steels were also estimated under the lattice fixed frame of reference so as to understand the complex mechanical behavior of TRIP steels after different isothermal bainitic transformation treatments. The effect of Si and Mn on transformation induced plasticity (TRIP) was discussed according to thermodynamic and kinetic analyses. It is recognized that Al also induces phase transformation in the steels but its TRIP effect is not as strong as that of Si.
基金supported by the National Natural Science Foundation of China(No.50171038)the Chinese Society for Metals and China-Belgium Bilateral Project(No.2001-242).
文摘Research status of high strength low alloy TRIP (transformation induced plasticity) steels for automobile structural parts is briefly described. Composition and microstruc-ture factors especially the morphology, size and volume fraction of retained austenite, which largely influence the strength and ductility of the steel, are reviewed and discussed one after another. Modelling of the inter-critical annealing and martempering processes as well as the designing of the TRIP steel aided by commercial software are introduced. Some special aspects of the dynamic mechanical properties of TRIP steel are firstly reported.
文摘The improvement of machining behavior of prehardened-mould steel for plastic is realized by using computer-aided composition design in this work. The results showed that the matrix composition of large sectional prehardened mould steel for plastic markedly influences the precipitation of non-metallic inclusion and the control of composition aided by Thermo-Calc software package minimizes the amount of detrimental oxide inclusion. In addition the modification of calcium is optimized in the light of composition design.
文摘With the two sublattices model, equilibrium compositions of ferrite (α) and austenite (γ) phases, as well as the volume percent of austenite (γ) in different TRIP steels are calculated. Concentration profiles of carbon, manganese, aluminum and silicon in these steels are also estimated under the lattice fixed frame of reference so as to identify if the equilibrium state is obtained. Through the comparison between the profiles after different time diffusion, the distribution of elements in phases is exhibited and the complex effect due to the mutual interaction of the elements on diffusion is discussed.
文摘MX 2 (M=Mo, W; X=S, Se) and DLC (a C: H and WC/C) are the two kinds of typical low friction coatings widely used in industry. The friction and wear properties of these two kinds of coatings marked as MOVIC, MOST, MoSe 2/Ni, WSe 2, a C: H and WC/C coatings were determined by fretting tests in ambient air of different humidity. The results show that the coefficient of friction of MX 2 coatings increases when the relative humidity of air increases whereas the coefficient of friction DLC coatings decreases with the increasing of relative humidity. MOVIC and WSe 2 coatings have a poor friction and wear resistance because of non basal planes (100) and (101) parallel to the surface in the MOVIC coating, or the rough and porous surface of WSe 2 coatings. Among these six coatings, MoSe 2/Ni and WC/C coatings have the highest wear resistance which seems to be unaffected by the relative humidity.
基金The study was financially supported by the key project of Science and Technology Commission of Shanghai Local Gov-ernment (No. 015211010), the National Natural Science Foundation of China (No. 50171038) and the China-Belgium bi-lateral project (No. 2001-242).
文摘Suitable optimization and simulation were performed using a powerful software package with a mature database as well as modem measurement facilities, which led to the successful designing and manufacturing of advanced steels. In the course of designing, the composition of a large section of prehardened mold steel for plastics was estimated so as to lower the quantities of oxide inclusions to change the type of carbides and to raise the machinability. The composition and process were adjusted to obtain satisfactory surface quality for the prevailing galvanization in transformation-induced plasticity （TRIP） steel. The refuting process of low-carbon steel was simulated in the light of both Thermo-Calc and Factsage. Thermodynamic and kinetic analyses were always conducted during the test and the procedure.
文摘The application of substitutional model in oxide systems, in comparison with that of sublattice model, is discussed.The results show that in the case of crystalline phases and liquid phases without molecular-like associates or theshortage of element in sublattice, these two models get consistent in the description of the formalism of Gibbs freeenergies of phases and obtain the same result of phase diagram calculation when the valence of the cations keep thesame.
文摘MoS coatings were prepared by means of bipolar-pulsed DC magnetron sputtering on different substrate type at various temperature. The structure and fretting behavior of MoS, coatings have been determined respectively by XRD and fretting tester in air of 10% to 90% RH and under the load of 1 to 10 N. With increasing substrate temperature, the edge orientation evolves in the MoSx coating, and the relative content of edge-to-basal orientation becomes large. The tribological performance of coatings gets deteriorated. Compared with MoS, coatings on TiN/H13, CrN/H13 and MoS /Ti multilayer, MoS coating on H13 substrate has a lower load bearing capacity, and worn away easily under higher normal load 5N or ION and in air of 90% RH during the fretting process. The friction and wear properties of MoS, coatings on TiN/H13 and CrN/H13 (dual-layer) are slight better than that of MoS, /Ti multilayer under the normal load tested and in air of<10%to90%RH.
