The casting structure, chemical composition segregation, dendrite arm space,inclusiona and during the CSP (compact strip production) rolling process were investigated. Theresults show that the CSP thin slab has a feat...The casting structure, chemical composition segregation, dendrite arm space,inclusiona and during the CSP (compact strip production) rolling process were investigated. Theresults show that the CSP thin slab has a feature of uniform fine grains, more columnar crystals,less central porosity and segregation etc. There is no great difference in macrostructure betweenthe CSP thin slab and conventional slab; however, the fine dendrite structure of the CSP slab ismore uniform. Moreover, the central porosity and segregation are obviously improved after the firstpass; and the dendrite is bent along the rolling direction rather than broken into pieces. Smallinclusions with the diameter less than 10 mum in the CSP slab are dominantly consisted of aluminatesformed by Al deoxidation and Ca treatment and not floating out of the melt. The large sizeinclusions found in the continuous casting slab are very few.展开更多
The effect of cooling rate on the microstructure of ZA48 alloy was investigated. The alloy was prepared using a relatively simple technique, i e, rapid cooling of the melt in a steel wedge mould. The dependence of mic...The effect of cooling rate on the microstructure of ZA48 alloy was investigated. The alloy was prepared using a relatively simple technique, i e, rapid cooling of the melt in a steel wedge mould. The dependence of microstructure on the cooling rate （about 40 to 10^3 K/s） was determined by the secondary dendrite arm space size measurement, optical microscopy（OM）, and transmission electron microscopy （TEM）. It is found that the matrix structure over a large cooling rate is composed of α-Al dendrite and eutectoid （α＋η）, the size of α-Al dendrite decreases with increasing cooling rate. The relationship between the cooling rate and the secondary dendrite arm space size has been established. TEM shows that a large number of small and dispersed precipitations can be seen in the primary α phase of tip region. Electron diffraction pattern shows that the precipitate phase is Zn3Mg2 phase.展开更多
The influence of pure La, pure Ce, (La+Ce) mischmetal on the dendritical arm space(LDAS) of ZL105 alloy in cylinderical casting was studied. The effects of adding amount of (La+ Ce) mischmetal on LDAs and ultimate te...The influence of pure La, pure Ce, (La+Ce) mischmetal on the dendritical arm space(LDAS) of ZL105 alloy in cylinderical casting was studied. The effects of adding amount of (La+ Ce) mischmetal on LDAs and ultimate tensile strength(b) were investigated, and the relationship between b and LDAS was founded. (La+Ce) mischmetal has stronger ability to refine LDAs than pure La or pure Ce. The proper adding amounts of it is 0.15% (mass fraction). LDAs has a remarkable effect on ah of casting, which can be predicted by the regression equation obtained in this work.展开更多
基金This work was financially supported by the National Natural Science Foundation of China (No. 50334010)
文摘The casting structure, chemical composition segregation, dendrite arm space,inclusiona and during the CSP (compact strip production) rolling process were investigated. Theresults show that the CSP thin slab has a feature of uniform fine grains, more columnar crystals,less central porosity and segregation etc. There is no great difference in macrostructure betweenthe CSP thin slab and conventional slab; however, the fine dendrite structure of the CSP slab ismore uniform. Moreover, the central porosity and segregation are obviously improved after the firstpass; and the dendrite is bent along the rolling direction rather than broken into pieces. Smallinclusions with the diameter less than 10 mum in the CSP slab are dominantly consisted of aluminatesformed by Al deoxidation and Ca treatment and not floating out of the melt. The large sizeinclusions found in the continuous casting slab are very few.
基金the financial supports from the National Science and Technology Major Project,China(No.Y2019-VII-0011-0151)the National Natural Science Foundation of China(No.51771190)。
文摘The effect of cooling rate on the microstructure of ZA48 alloy was investigated. The alloy was prepared using a relatively simple technique, i e, rapid cooling of the melt in a steel wedge mould. The dependence of microstructure on the cooling rate （about 40 to 10^3 K/s） was determined by the secondary dendrite arm space size measurement, optical microscopy（OM）, and transmission electron microscopy （TEM）. It is found that the matrix structure over a large cooling rate is composed of α-Al dendrite and eutectoid （α＋η）, the size of α-Al dendrite decreases with increasing cooling rate. The relationship between the cooling rate and the secondary dendrite arm space size has been established. TEM shows that a large number of small and dispersed precipitations can be seen in the primary α phase of tip region. Electron diffraction pattern shows that the precipitate phase is Zn3Mg2 phase.
文摘The influence of pure La, pure Ce, (La+Ce) mischmetal on the dendritical arm space(LDAS) of ZL105 alloy in cylinderical casting was studied. The effects of adding amount of (La+ Ce) mischmetal on LDAs and ultimate tensile strength(b) were investigated, and the relationship between b and LDAS was founded. (La+Ce) mischmetal has stronger ability to refine LDAs than pure La or pure Ce. The proper adding amounts of it is 0.15% (mass fraction). LDAs has a remarkable effect on ah of casting, which can be predicted by the regression equation obtained in this work.
