The effect of composite agglomeration process(CAP) on fluoric iron concentrates sintering was investigated.The yield and quality of the sinter are greatly improved when using CAP assisted with heat airflow and enhanci...The effect of composite agglomeration process(CAP) on fluoric iron concentrates sintering was investigated.The yield and quality of the sinter are greatly improved when using CAP assisted with heat airflow and enhancing magnesium oxide(MgO) contents.For conventional sintering of fluoric iron concentrate,due to lower viscosity of binding phase and higher fluidity of liquid phase,the sinter is formed with large thin-walled holes and the strength of the sinter is deteriorated consequently.The novel process forms composite agglomerate in which acid pellets are embedded in basic sinter.The pellets are solid with interconnecting crystals of hematite(Fe2O3) and magnetic(Fe3O4).For basic sintering,after adding MgO,the viscosity of the melting phase increases and the fluidity decreases;and calcium and aluminum silico-ferrites and magnesium ferrite are formed with perfect crystals and good sintering microstructure.展开更多
The mechanical properties of graphene reinforced composites are often hampered by challenges related to the dispersion and aggregation of graphene within the matrix.This paper explores the mechanism of cooling rate,pr...The mechanical properties of graphene reinforced composites are often hampered by challenges related to the dispersion and aggregation of graphene within the matrix.This paper explores the mechanism of cooling rate,process temperature,and process pressure’s influence on the agglomeration behavior of graphene and the tensile response of composites from a computer simulation technology,namely molecular dynamics.Our findings reveal that the cooling rate exerts minimal influence on the tensile response of composites.Conversely,processing temperature significantly affects the degree of graphene aggregation,with higher temperatures leading to the formation of larger-sized graphene clusters.In contrast,processing pressure exhibits negligible impact on the degree of graphene aggregation,and increasing pressure effectively mitigates the formation of large-sized graphene clusters.Moreover,we elucidate the intrinsic factors governing the mechanical response to variations in processing parameters.Notably,we observe that the stretching process facilitates the decomposition of large-sized graphene clusters into smaller ones.This research contributes to the advancement of lightweight metal matrix composites by offering insights into optimizing processing parameters.Additionally,it provides crucial theoretical underpinnings for developing high-performance graphene-reinforced composites.展开更多
Effect of distribution of iron concentrates between pelletized and matrix feed on the preparation of blast furnace burdens from two different kinds of fine iron concentrates (magnetite and hematite) by composite agglo...Effect of distribution of iron concentrates between pelletized and matrix feed on the preparation of blast furnace burdens from two different kinds of fine iron concentrates (magnetite and hematite) by composite agglomeration process (CAP) was explored. It was found that when the mass ratio of iron concentrate A (magnetite) to iron concentrate B (hematite) in the mixed feed was constant, the proportion of iron concentrate A in the pelletized and matrix feed significantly affected the quality of CAP products. Particularly, as the proportion of iron concentrate A in the pelletized feed increased from 0 to 100%, the yield decreased from 82.11% to 79.19% and the tumbler index decreased from 71.33% to 68.27%. The mineralization characterization results indicated that when 100% iron concentrate A was used as the pelletized feed, the crystallization styles of the outer layer and the inner layer of the pellet were different, and a lot of pores exist around hematite and magnetite phases in the pelletized part, with the weak connection of pelletized and matrix part, resulting in poor strength of agglomeration product.展开更多
TiC particle reinforced 420 stainless steel matrix composites were fabricated, and the microstructure, tensile properties and wear resistance of the composites were studied. The experimental results indicate that the ...TiC particle reinforced 420 stainless steel matrix composites were fabricated, and the microstructure, tensile properties and wear resistance of the composites were studied. The experimental results indicate that the distribution of TiC particles with size of 5 to 10 μm in diameter is uniform if the volume fraction of TiC is lower than 6%. However, slight agglomeration can be observed when the TiC content exceeds 6%. With the increase of TiC content the tensile and yield strength of the composites prepared increases and reaches the maximum when the volume fraction of TiC increases to 5%. Further increase of TiC content causes reductions of yield and tensile strength. The ductility of the composites shows a monotone decrease with the increase of TiC addition. The introduction of TiC into 420 stainless steel results in significant improvement on wear resistance, which reaches a steady level when the volume fraction of TiC increases to 11% and does not show obvious variation if the TiC content is further increased.展开更多
基金Project(50725416) supported by the National Science Fund for Distinguished Young Scholars
文摘The effect of composite agglomeration process(CAP) on fluoric iron concentrates sintering was investigated.The yield and quality of the sinter are greatly improved when using CAP assisted with heat airflow and enhancing magnesium oxide(MgO) contents.For conventional sintering of fluoric iron concentrate,due to lower viscosity of binding phase and higher fluidity of liquid phase,the sinter is formed with large thin-walled holes and the strength of the sinter is deteriorated consequently.The novel process forms composite agglomerate in which acid pellets are embedded in basic sinter.The pellets are solid with interconnecting crystals of hematite(Fe2O3) and magnetic(Fe3O4).For basic sintering,after adding MgO,the viscosity of the melting phase increases and the fluidity decreases;and calcium and aluminum silico-ferrites and magnesium ferrite are formed with perfect crystals and good sintering microstructure.
基金supported by the National Natural Science Foundation of China (Grant No.52475405,52471164,and 52231004)Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University (No.CX2022039).
文摘The mechanical properties of graphene reinforced composites are often hampered by challenges related to the dispersion and aggregation of graphene within the matrix.This paper explores the mechanism of cooling rate,process temperature,and process pressure’s influence on the agglomeration behavior of graphene and the tensile response of composites from a computer simulation technology,namely molecular dynamics.Our findings reveal that the cooling rate exerts minimal influence on the tensile response of composites.Conversely,processing temperature significantly affects the degree of graphene aggregation,with higher temperatures leading to the formation of larger-sized graphene clusters.In contrast,processing pressure exhibits negligible impact on the degree of graphene aggregation,and increasing pressure effectively mitigates the formation of large-sized graphene clusters.Moreover,we elucidate the intrinsic factors governing the mechanical response to variations in processing parameters.Notably,we observe that the stretching process facilitates the decomposition of large-sized graphene clusters into smaller ones.This research contributes to the advancement of lightweight metal matrix composites by offering insights into optimizing processing parameters.Additionally,it provides crucial theoretical underpinnings for developing high-performance graphene-reinforced composites.
基金supported by the National Natural Science Foundation of China under Grant U1960114,51774337,and U1660206the Open Sharing Fund for the Large-scale Instruments and Equipments of Central South University under Grant CSUZC201905the Fundamental Research Funds for the Central Universities of Central South University under Grant 2018zzts220.
文摘Effect of distribution of iron concentrates between pelletized and matrix feed on the preparation of blast furnace burdens from two different kinds of fine iron concentrates (magnetite and hematite) by composite agglomeration process (CAP) was explored. It was found that when the mass ratio of iron concentrate A (magnetite) to iron concentrate B (hematite) in the mixed feed was constant, the proportion of iron concentrate A in the pelletized and matrix feed significantly affected the quality of CAP products. Particularly, as the proportion of iron concentrate A in the pelletized feed increased from 0 to 100%, the yield decreased from 82.11% to 79.19% and the tumbler index decreased from 71.33% to 68.27%. The mineralization characterization results indicated that when 100% iron concentrate A was used as the pelletized feed, the crystallization styles of the outer layer and the inner layer of the pellet were different, and a lot of pores exist around hematite and magnetite phases in the pelletized part, with the weak connection of pelletized and matrix part, resulting in poor strength of agglomeration product.
文摘TiC particle reinforced 420 stainless steel matrix composites were fabricated, and the microstructure, tensile properties and wear resistance of the composites were studied. The experimental results indicate that the distribution of TiC particles with size of 5 to 10 μm in diameter is uniform if the volume fraction of TiC is lower than 6%. However, slight agglomeration can be observed when the TiC content exceeds 6%. With the increase of TiC content the tensile and yield strength of the composites prepared increases and reaches the maximum when the volume fraction of TiC increases to 5%. Further increase of TiC content causes reductions of yield and tensile strength. The ductility of the composites shows a monotone decrease with the increase of TiC addition. The introduction of TiC into 420 stainless steel results in significant improvement on wear resistance, which reaches a steady level when the volume fraction of TiC increases to 11% and does not show obvious variation if the TiC content is further increased.
