Xinli Song Zexi Yuan Juan Jia Di Wang Pinghe Li Zhaojun Deng
材料科学技术（英文）
The cold-rolled (75% reduction ratio) Ti-IF (interstitial-free) steels of 1 mm thickness were recrystallized by annealing at 810°C for different times. The microstructure, mechanical properties and phosphorus segregation at grain boundary were investigated by means of optical microscopy (OM), tensile testing and field emission transmission electron microscopy (FE-TEM). It was observed that recrystallization was completed after annealing at 810°C for 180 s. The yield strength and tensile strength decreased as annealing time increased. The FE-TEM observation showed that after the annealing treatment, the grain boundary was broadened and the dislocations with higher density of phosphorus atoms and phosphide at grain boundaries became evident. The amount of phosphorus segregated at grain boundaries increased with annealing time.
关键词:
IF (interstitial-free) steel
,
Segregation
,
Mechanical properties
,
Recrystallization annealing
Xinli Song Zexi Yuan Juan Jia Di Wang Pinghe Li Zhaojun Deng
材料科学技术（英文）
The cold-rolled (75% reduction ratio) Ti-IF (interstitial-free) steels of 1 mm thickness were recrystallized by annealing at 810°C for different times. The microstructure, mechanical properties and phosphorus segregation at grain boundary were investigated by means of optical microscopy (OM), tensile testing and field emission transmission electron microscopy (FE-TEM). It was observed that recrystallization was completed after annealing at 810°C for 180 s. The yield strength and tensile strength decreased as annealing time increased. The FE-TEM observation showed that after the annealing treatment, the grain boundary was broadened and the dislocations with higher density of phosphorus atoms and phosphide at grain boundaries became evident. The amount of phosphorus segregated at grain boundaries increased with annealing time.
关键词:
IF (interstitial-free) steel
,
Segregation
,
Mechanical properties
,
Recrystallization annealing
X.Y. Pang Z.Q. Liu S.Q. Wang J.K. Shang
材料科学技术（英文）
Density functional theory was employed to investigate the bismuth segregation at Cu/Cu3Sn(010) interface. Five initial constructions were introduced by adopting the adhesion energy criterion. Among them, the so-called "between-Cu" construction in which the interface Cu atoms of Cu slab locate along Cu-Cu bond direction in Cu3Sn slab was found to be the most energy-favored at an adhesion energy of 1.96 J/m2. Based on this construction, five possible segregation sites were examined, and the most likely segregation site was determined with adhesion energy as low as 1.06 J/m2, which was almost half of the initial one. Comparing with other sites' adhesion energies, it was concluded that size effect took a large part in embrittlement. The analyses of atomic structure and electronic density revealed that the slabs shifted away from interfaces due to bismuth segregation, and the atoms around Bi atom were pressed away. This calculated work agreed qualitatively with reported experimental results.
关键词:
First-principles calculation
,
segregation
,
Bismuth
,
interface
,
SnBi solder.
