This study is focused on the effects of electroslag remelting by prefused slag （CaO, Al2O3, and CaF2） on macrostructure and reduction of inclusions in the medical grade of 316LC （316LVM） stainless steel. Analysis ...This study is focused on the effects of electroslag remelting by prefused slag （CaO, Al2O3, and CaF2） on macrostructure and reduction of inclusions in the medical grade of 316LC （316LVM） stainless steel. Analysis of the obtained results indicated that for production of a uniform ingot structure during electroslag remelting, shape and depth of the molten pool should be carefully controlled. High melting rates led to deeper pool depth and interior radial solidification characteristics, while decrease in the melting rates caused more reduction of nonmetallic inclusions. Large shrinkage cavities formed during the conventional casting process in the primary ingots were found to be the cause of the fluctuation in the melting rate, pool depth and extension of equiaxed crystals zone.展开更多
Effects of multiple strengthening treatments （i.e. ag mechanical properties and stability of nanoscale prec in this research. Various tests such as hardness, tensi ng either at three or four consecutive temperatures...Effects of multiple strengthening treatments （i.e. ag mechanical properties and stability of nanoscale prec in this research. Various tests such as hardness, tensi ng either at three or four consecutive temperatures） on pitated phases in an AA2090 alloy have been evaluated e, electrical resistance, differential scanning calorimetric （DSC）, and transmission electron microscopy （TEM） have been performed. The results show that the ultimate tensile strength （UTS） and the yield strength of the samples aged at four consecutive temperatures （i.e. natural aging＋190℃＋150℃＋100℃） can be increased approximately to 660 and 610 MPa, respectively. It is also found that precipitation of T1 phase occurs during multiple aging process of the alloy and the higher amounts of enthalpies shown in DSC charts are linked to higher volume fraction of this precipitate. Furthermore, TEM observations reveal that T1 phase has plate shape morphology and its crystal structure is in the form of hcp with lattice parameters of a=0.467 nm and c=0.878 nm.展开更多
In this research, the dynamic recrystallization （DRX） behavior of an as-cast precipitation hardenable （PH） stainless steel was investigated by conducting hot compression tests at temperatures between 950-1150℃ an...In this research, the dynamic recrystallization （DRX） behavior of an as-cast precipitation hardenable （PH） stainless steel was investigated by conducting hot compression tests at temperatures between 950-1150℃ and under strain rates of 0.001-1 s^-1. The flow stress curves show that the DRX is responsible for flow softening during hot compression. The effects of temperature and strain rate on the strain and stress corresponding to peak point （εp and σp） of flow curve were analyzed individually. It is realized that, they increase with strain rate and decrease with temperature. The relationship between Zener-Hollomon parameter （Z） and εp was investigated and the equation of εp=4.3×10^-4^0.14 was proposed. The strain for the maximum rate of DRX （εmax） was determined under different deformation conditions. Therefore, it is realized that it increases with Z parameter and vise versa. On the basis of obtained results, the equation of εmax=9.5 × 10^-4Z0.12 was proposed.展开更多
文摘This study is focused on the effects of electroslag remelting by prefused slag （CaO, Al2O3, and CaF2） on macrostructure and reduction of inclusions in the medical grade of 316LC （316LVM） stainless steel. Analysis of the obtained results indicated that for production of a uniform ingot structure during electroslag remelting, shape and depth of the molten pool should be carefully controlled. High melting rates led to deeper pool depth and interior radial solidification characteristics, while decrease in the melting rates caused more reduction of nonmetallic inclusions. Large shrinkage cavities formed during the conventional casting process in the primary ingots were found to be the cause of the fluctuation in the melting rate, pool depth and extension of equiaxed crystals zone.
文摘Effects of multiple strengthening treatments （i.e. ag mechanical properties and stability of nanoscale prec in this research. Various tests such as hardness, tensi ng either at three or four consecutive temperatures） on pitated phases in an AA2090 alloy have been evaluated e, electrical resistance, differential scanning calorimetric （DSC）, and transmission electron microscopy （TEM） have been performed. The results show that the ultimate tensile strength （UTS） and the yield strength of the samples aged at four consecutive temperatures （i.e. natural aging＋190℃＋150℃＋100℃） can be increased approximately to 660 and 610 MPa, respectively. It is also found that precipitation of T1 phase occurs during multiple aging process of the alloy and the higher amounts of enthalpies shown in DSC charts are linked to higher volume fraction of this precipitate. Furthermore, TEM observations reveal that T1 phase has plate shape morphology and its crystal structure is in the form of hcp with lattice parameters of a=0.467 nm and c=0.878 nm.
文摘In this research, the dynamic recrystallization （DRX） behavior of an as-cast precipitation hardenable （PH） stainless steel was investigated by conducting hot compression tests at temperatures between 950-1150℃ and under strain rates of 0.001-1 s^-1. The flow stress curves show that the DRX is responsible for flow softening during hot compression. The effects of temperature and strain rate on the strain and stress corresponding to peak point （εp and σp） of flow curve were analyzed individually. It is realized that, they increase with strain rate and decrease with temperature. The relationship between Zener-Hollomon parameter （Z） and εp was investigated and the equation of εp=4.3×10^-4^0.14 was proposed. The strain for the maximum rate of DRX （εmax） was determined under different deformation conditions. Therefore, it is realized that it increases with Z parameter and vise versa. On the basis of obtained results, the equation of εmax=9.5 × 10^-4Z0.12 was proposed.
