The oxygen relief/absorption,superconduc—tivity and structure of(Bi<sub>1-x</sub>Pb<sub>x</sub>)<sub>2</sub>Sr<sub>2</sub>Ca<sub>2</sub>—Cu<sub>3</sub>O<sub>y
A large number of δ particles precipitated atlow-angle grain boundaries have been observed byTEM in a dilute A1-Li-Zn-Zr alloy during ageingat the suitable tem
1.IntroductionThe research of metal forming theoryand technology always takes an importantplace in materials science and engineering.However,in a long period,th