CHENG Tianyi Beijing Institute of Technology
,
Beijing
,
ChinaCANTORB University of Oxford
,
UKMcLEANM FLOWERHM Imperial College
,
UK CHENG Tianyi
,
associate professor
,
Faculty of Metallography
,
Beijing Institute of Technology
,
Beijing 100081
,
China
金属学报(英文版)
In rapidly solidified Ni-34.6 at-% Al alloy,when the cooling the rate during solidification reached the order of 10~6 K/s,the size of the microstructures,such as the grains and substructure of the martensite,decreased dramatically.The various kinds of interfaces with high density and homogeneous distribution resisted effectively the propagation of the cracks and resulted in localized plastic deformation ahead of the tips of microcracks.The ductility and toughness at room temperature of the Ni-rich NiAl may be improved considerably.
关键词:
NiAl
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null
,
null
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null
ZHAO Jiarong YANG Jie Wuhan Iron and Steel University
,
Wuhan
,
China ZHAO Jiarong
,
associate professor
,
Faculty of Rolling
,
Wuhan Iron and Steel University
,
Wuhan 430081
,
China
金属学报(英文版)
Based on the analyses of hot-deformation mechanism of the steel,a new constitutive equation describing the flow stress of steels was derived.The flow stress data of steel 55SiMnVB have been determined at 900—1200℃,strain rates of 1—100s~(-1)and true-strain of 0.08—0.8.An available evaluated formula on the flows tress has been obtained by means of non-linear regression.It can express clearly the physical process of hot-deformation.
关键词:
flow stress
,
null
,
null
FU Changpu HAN Yong Shaanxi Mechanical Engineering Institute
,
Xi'an
,
China FU Changpu
,
associate professor
,
Department of Materials Engineering
,
Shaanxi Mechanical Engineering Institute
,
Xi'an 710048
,
China
金属学报(英文版)
Studies were made of the effect of tempering at temperatures from 25 to 750℃ for 0.5 to 100 h on changes of hardness,precipitated phase and its alloying element content as well as activation energy of tempering for quenched steel 20Cr11MoVNbNB.Tempering of the steel at temperatures below 400℃ may be controlled by the diffusion of C atoms in α-Fe,and above 400℃,by diffusion of Cr,also Mo or V,in α-Fe.
关键词:
steel 20Cr11MoVNbNB
,
null
,
null
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null
CHAI Huifen RUAN Zheng FAN Quncheng (Xi'an Jiaotong University
,
Xi'an
,
China CHAI Huifen
,
associate professor
,
Department of Materials
,
Xi'an Jiaotong University
,
Xi'an 710049
,
China
金属学报(英文版)
The cyclic behaviours of two prestrained materials with different slip modes have been com- pared.From the analysis of hysterisis loops,it is suggested that the decrease in back stress dominates the cyclic process of Cu-Zn alloy with planar slip mode,while the decrease in frictional stress is the main factor affecting the behaviour of Cu with wavy slip mode.The re- lation between the dislocation configuration and internal stress has been also discussed.By means of the relation just mentioned,the variations of dislocation configuration before and after fatigue of the two materials,the differences in their softening mechanism and mechani- cal behaviour could be interpreted.
关键词:
slip mode
,
null
,
null
,
null
TIAN Baohong ZHENG Shi'an WU Lei Luoyang Institute of Technology
,
Luoyang
,
China ZHENG Shi'an
,
associate professor
,
Department of Materials Engineering
,
Luoyang Institute of Technology
,
Luoyang 471039
,
China
金属学报(英文版)
Determination was carried out of fatigue crack propagation rate of steel 65Cr5Mo3W2VSiTi (LM2)with various bainite contents and M/B duplex structure tempered at various tempera- tures.The threshold value of fatigue for each processing was estimated by experimental data. The mechanism for fatigue crack propagation of M/B duplex structure in steel LM2 seems to be non-continuous.The calculated fatigue crack micro-propagation rates are found to agree with the experimental data.
关键词:
duplex structure
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null
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null
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null
