Lingzhong DU
,
Binshi XU
,
Shiyun DONG
,
Xin LI
,
Hua YANG
,
Weiyi TU
,
Zixin ZHU
材料科学技术（英）
Ni-matrix composite coating containing Al2O3 nano-particles is prepared by brush plating. The effects of the nano-particles on the microstructure, microhardness and tribological properties of the composite coating under the lubrication of a diesel oil containing sand are investigated. The results show that the microstructure of the composite coating is finer than that of the pure nickel coating due to the codeposition of the nano-particles. When the nano-particle concentration in the electroplating bath reaches 20 g/L, the microhardness, and wear resistance of the composite coating is as much as 1.6 times and 1.3～2.5 times of those of the pure nickel coating respectively. The main hardening mechanism of the composite coating is superfine crystal grain strengthening and dispersion strengthening. The composite coating is characterized by scuffing as it slides against Si3N4 under the present test conditions.
关键词:
Brush plating
,
null
,
null
,
null
Lianquan GUO
,
Changxiang MA
,
Shuai WANG
,
He MA
,
Xin LI
材料科学技术（英）
The adsorption of hydrogen onto single-walled carbon nanotubes (SWCNTs) was studied by molecular dynamics (MD) simulation. It was found that the hydrogen molecules distribute regularly inside and outside of the tube. Density distribution was computed for H2 molecule. Theoretical analysis of the result showed the multilayer adsorption mechanism of SWCNTs. The storage of H2 in SWCNTs is computed, which provides essential theoretical reference for further study of hydrogen adsorption in SWCNTs.
关键词:
Single-walled carbon nanotubes
,
null
,
null
,
null
Fuxian ZHU
,
Xin LI
,
Yanchun LIU
,
Xianghua LIU
,
Guangfu SHE
,
Zhongping ZHANG
材料科学技术（英）
Effect of different cooling history on yield ratio of HP295 steel for welded gas cylinder was studied and the result implied that both fine microstructure and good mechanical properties can be attained by using two-stage cooling and controlling the coiling temperature. The yield ratio of HP295 steel sheet was reduced to less than 0.8 by two-stage cooling process. The pass percent of yield ratio was enhanced from less than 90% to 100%. The mechanical properties satisfied the criteria of GB6653-1994.
关键词:
HP295 steel sheet
,
屈强比
,
两段式冷却
,
卷取温度
Daming XU
,
Qingmei YU
,
Xin LI
,
Geying AN
材料科学技术（英）
Recently proposed mathematical model for mold filling processes under centrifugal force field conditions and the computer codes were first tested through the sample simulation of gravity mold filling process for a benchmark plate-casting, which were compared with quoted experimental observations. The model and the developed computer program were then applied to the numerical simulation of centrifugal field mold filling processes for a thin-section casting with a titanium alloy melt of assumed viscosity of 1.2 and 12.0 mm2/s, respectively. The computation result comparison shows that the flow behaviors of the filling melts are basically similar to each other although the less viscous melt tends to fill into the thin section casting cavity faster.
关键词:
Centrifugal casting
,
null
,
null
,
null
