Rongshi CHEN
,
J.J.Bl
,
in
,
M.Sue'ry
,
Qudong WANG
,
Enhou HAN
材料科学技术（英）
The effect of extrusion on grain refinement has been studied in the AZ91 cast ingots. It is found that grain size smaller than 10μm can be obtained by the extrusion processing. Vickers hardness measurements were also carried out to evaluate the effect of these processes on the room temperature mechanical properties. ...
关键词:
Magnesium alloy
,
null
Rongchang ZENG
,
Enhou HAN
材料科学技术（英）
The corrosion morphologies of aged magnesium alloy AZ80 were investigated by immersion corrosion tests, scanning electron microscopy (SEM), electrochemical measurement. The T5 heat treatment was carried out in a vacuum furnace, holding for 16 h at 177℃, and then cooling in air. The results showed intergranular corrosion (IGC) occurred as an aged AZ80 sample was immersed in 3.5 wt pct NaCl aqueous solution for 1 h and the narrow path attack progressed predominantly along the bulk β phase in the grain boundaries or took place in the eutectic areas. IGC was attributed to the network distribution of β phase along the grain boundaries, the depleted aluminium in the precipitation areas and the breakdown potential.
关键词:
Magnesium alloy
,
null
,
null
,
null
Guangbin RAO
,
Jianqiu WANG
,
We KE
,
Enhou HAN
材料科学技术（英）
The fatigue crack propagation behavior of TiNi50.6 shape memory alloy was studied. The experiment results showed that the crack propagation properties of this alloy display difference and similarity in comparison with common metallic materials. Because of the stress concentration there was stress induced martensite transformation (SIMT) near the crack tip though the nominal stress was lower than the threshold stress of SIMT. The position and the amount of SIMT was in situ observed by a quester remote measurement system (QRMS). The observation results showed that the position of SIMT was beside the crack tip and was not in the plastic, zone of common metallic materials (in front of the crack tip). The SIMT zone at an angle of about 45 degrees to the direction of the crack propagation, like a butterfly, appeared in the loading process, disappeared in the unloading process and grew larger with the increase of DeltaK. The crack propagation rate(da/dN) followed the linear law in Ig-Ig plot. Observation of the crack surface showed fatigue striation clearly. The relationship between the site and the size of the plastic zone and the SIMT zone is discussed and a model is given to explain both the similarity and the difference of the crack propagation property of TiNi50.6 to common metal materials.
关键词:
Xueyuan ZHANG
,
Enhou HAN
,
Yuanlong DU
材料科学技术（英）
An in-situ probe technique with an outward attached type of electrochemical sensor for inspection and evaluation of the susceptibility to sulfide stress corrosion cracking (SSCC) and hydrogen embrittlement (HE) of pipeline/vessel was developed. The relationship between SSCC/HE susceptibility of steel UNS G10180 and UNS G11190 and I-H was determined by the measurement of the stable hydrogen permeation rate (I-H) and the study of SSCC/HE susceptibility of the above two steels in TM-01-77 solution. Environmental sensitive cracking (ESC) of UNS G10180 and UNS G11190 steels can be inspected, evaluated, judged by the combination with the microcomputer system (MCS)/periphery attachment and the designed software. The results give an important insurance for safety control of the pressurized pipeline/vessel operated in the environment with H2S.
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