The effect of cryogenic temperatures on the mechanical properties and fracture mechanism of SnAgCu−SnPb mixed solder joints was investigated.The results showed that the tensile strength of mixed solder joints first in...The effect of cryogenic temperatures on the mechanical properties and fracture mechanism of SnAgCu−SnPb mixed solder joints was investigated.The results showed that the tensile strength of mixed solder joints first increased with the increase of Pb content and reached its maximum at 22.46 wt.%Pb;subsequently,it decreased as Pb content increased.However,cryogenic temperatures improved the tensile strength of the solder joints.Both Pb content and cryogenic temperature caused the fracture mode of the mixed solder joints to change;however,temperature remained the main influencing factor.As the temperature fell from 298 to 123 K,the failure pattern in the solder joints transformed from ductile fracture to quasi-ductile fracture to quasi-brittle fracture and finally,to brittle fracture.展开更多
Four tools with different pin centerline deviations were fabricated to friction stir weld(FSW)thick plates of Al-Mg-Zn-Cu alloys.The results show that,compared with the pin without pin centerline deviation,the applyin...Four tools with different pin centerline deviations were fabricated to friction stir weld(FSW)thick plates of Al-Mg-Zn-Cu alloys.The results show that,compared with the pin without pin centerline deviation,the applying of pin centerline deviation is favorable to improve the flowability of plastic material,enlarging the size of nugget zone,refining the grains and reprecipitated phase particles,enhancing the degrees of dynamic recrystallization and quantity of high angle grain boundaries owing to higher temperature and bigger eccentric force,resulting in the increase of strain hardening.Especially for the used pin with a centerline deviation of 0.2 mm,the highest average hardness and best metallurgical properties of thick FSW joints are produced,and which are consistent with the microstructure evolution and recrystallization behavior.Moreover,the fracture mode of the joints produced by the pins with centerline deviation from 0 mm to 0.3 mm changes gradually from a brittle fracture in the nugget zone(NZ)to a ductile failure in the HAZ.展开更多
基金The authors are grateful for the financial supports from the National Natural Science Foundation of China(No.51965044)the Aeronautical Science Foundation of China(No.20185456005).
文摘The effect of cryogenic temperatures on the mechanical properties and fracture mechanism of SnAgCu−SnPb mixed solder joints was investigated.The results showed that the tensile strength of mixed solder joints first increased with the increase of Pb content and reached its maximum at 22.46 wt.%Pb;subsequently,it decreased as Pb content increased.However,cryogenic temperatures improved the tensile strength of the solder joints.Both Pb content and cryogenic temperature caused the fracture mode of the mixed solder joints to change;however,temperature remained the main influencing factor.As the temperature fell from 298 to 123 K,the failure pattern in the solder joints transformed from ductile fracture to quasi-ductile fracture to quasi-brittle fracture and finally,to brittle fracture.
基金financially supported by the National Natural Science Foundation of China(NSFC)(Nos.52164045,52005240,51874179,51865035)the Natural Science Foundation Project of Jiangxi Province of China(No.20202BAB214019)the Key Laboratory Fund Project(No.EG202080409)。
文摘Four tools with different pin centerline deviations were fabricated to friction stir weld(FSW)thick plates of Al-Mg-Zn-Cu alloys.The results show that,compared with the pin without pin centerline deviation,the applying of pin centerline deviation is favorable to improve the flowability of plastic material,enlarging the size of nugget zone,refining the grains and reprecipitated phase particles,enhancing the degrees of dynamic recrystallization and quantity of high angle grain boundaries owing to higher temperature and bigger eccentric force,resulting in the increase of strain hardening.Especially for the used pin with a centerline deviation of 0.2 mm,the highest average hardness and best metallurgical properties of thick FSW joints are produced,and which are consistent with the microstructure evolution and recrystallization behavior.Moreover,the fracture mode of the joints produced by the pins with centerline deviation from 0 mm to 0.3 mm changes gradually from a brittle fracture in the nugget zone(NZ)to a ductile failure in the HAZ.
