Z.Y. Lu 1)
,
S.M.An 2)
,
B.H.Cuo 2)
,
W.M.Li 1)
,
Y.Mei
,
Y.L.Xia 2) and J.Xu 2) 1) Department of Mechanical Engineering
,
Yangzhou University
,
Yangzhou 225009
,
China 2) Dalian University of Technology
,
Dalian 116024
,
China
金属学报(英文版)
This study raised a new assisted technique used for chemical vapor deposition (CVD) in which a laser beam irradiated the surface of substrate and simultaneously the plasma surroundings created in the reactive room, but both laser and plasma were at lower energy level in order to perform easily. The chemical vapor deposition reaction could be performed only just using simultaneously above two assisted methods. If not, the reaction could not be performed, too. It is laser plasma assisted chemical vapor deposition (LPCVD). For these reasons, a LPCVD device had been designed and manufactured, and was carried on practical operation. The results indicated that this technique is successful and feasible. Acting on the system of SiH 4 NH 3 N 2 with both CO 2 laser and RF plasma, expectant film of silicon nitride had been obtained on the surface of stainless steel.
关键词:
CVD
,
null
,
null
,
null
J.H.Liu 1) and S.H.Jiang 1) and M.Yao 2) 1) Department of mechanical Engineering
,
Engineering college
,
Yangzhou University
,
Yangzhou 225009
,
China 2) Department of Material Science
,
Yanshan University
,
Qinhuangdao 066000
,
China
金属学报(英文版)
By using a self-made thermal fatigue test machine of outer-constraint mode, the influence of top-temperature of thermal cycle T t on thermal stress-strain and thermal fatigue behavior of an industrial pure iron was investigated. The T t was varied from stress/strain 773K to 1073K. The results show that, increasing of T t , the thermal stress-strain cycles can be classified into four types, they are: compressive stress cycle; compressive strain-tensile stress cycle; compressive strain-tensile stress cycle than changing to compressive tensile plastic strain cycle; and finally, compressive tensile plastic strain cycle. It is also revealed that certain relationship does exist between thermal fatigue life and characteristics of thermal stress/strain cycle. When compressive tensile plastic strain cycle were appear by increasing of T t , thermal fatigue life decreasing rapidly. The concept of thermal fatigue transition temperature, and determining method were put up in this thesis.
关键词:
thermal fatigue
,
null
Z.X. Wu Engineering College
,
Yangzhou University
,
Yangzhou 225009
,
China
金属学报(英文版)
In order to understand which parameters, such as the number of cracks and the total crack length is the useful indicators of fatigue damage, rotatory bending fatigue tests are carried out using smooth specimens of a medium-carbon steel. The behavior of short crock propagation and the evolution of surface cracks during fatigue are examined. The aim of this paper is to study how these damage parameters are correlated with the process of fatigue in order to evaluate the effectiveness of damage detection methods.
关键词:
fatigue damage
,
null
,
null
,
null
