材料期刊网

Oxygen Relief/Absorption and Superconductivity of Bi-Pb-Sr-Ca-Cu-O Compounds

QIN Zuoxiang , ZHANG Yansheng , ZHU Naiping Department of Materials Engineering , Dalian Railway Institute , Dalian , 116022 , China.Institute of Metal Research , Academia Sinica , Shenyang , 110015 , China.

材料科学技术（英）

The oxygen relief/absorption,superconduc— tivity and structure of(Bi_(1-x)Pb_x)_2Sr_2Ca_2— Cu_3O_y compounds have been studied by TGA, electrical resistance measurement and X-ray diffraction.The amount of oxygen which can be re- leased and superconductivity of the compounds are correlative to Pb content.The release of oxygen in- creases when x less than 0.2 and decreases when x exceeds 0.2 with increasing x.The appropriate con- tent of Pb for superconductivity is in the range of 0.1

关键词: oxygen relief/absorption , null , null , null

The Use of Image Analysis to Simulate Growth Kinetics of Ferrite by Carbon Diffusion in SG Cast Iron

HU Yixiang Central Laboratory , Dalian Locomotive Factory , Dalian , 116022 , China.

材料科学技术（英）

关键词: image analysis , null , null

Low Ductility at Elevated Temperatures of the Cryogenic and Non-magnetic Steel Fe-23Mn-4Al-SCr-0.3C

TIAN Xing ZHANG Yansheng Dalian Railway Institute , Dalian , 116022 , China

材料科学技术（英）

The origin of low ductility at elevated tempera- ture in the cryogenic and non-magnetic steel Fe-23Mn-4Al-5Cr-0.3C was investigated by means of impact test at elevated temperatures,opti- cal microscope,SEM and TEM.The experimental results indicate that the impact toughness lowers with increasing testing temperature,and exhibits a low trough of ductility from 865℃ to 1050℃ and a peak value at 1150℃.The intergranular fracture occurs in the temperature region of low ductility and the transgranular ductile rupture below this re- gion principally.There is a process of precipitating, gathering,growing,and dissolution of carbide (FeMnCr)_(23)C_6 and AlN between 500℃ and 1000℃.The coalescence of microvoids caused by the process at grain boundaries results in the intergranular fracture and the low ductility at ele- vated temperatures.

关键词: ductility , null , null , null , null