TIAN Xing ZHANG Yansheng Dalian Railway Institute
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Dalian
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116022
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China
材料科学技术(英文)
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
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CUI Juan
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LIU Yazheng
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PAN Hui
,
GAO Lifeng
钢铁研究学报(英文版)
The microsturctural transformation of austenite grain, pearlite interlamellar spacing, and lamellar cementite thickness of spring steel 60Si2MnA for railway were studied in the hotrolled and reheated states. Furthermore, the effect of microstructural characterization on its final mechanical properties was discussed. The results showed that as far as 60Si2MnA, the pearlite interlamellar spacing determined the hardness, whereas, the austenite grain determined the toughness. Compared with microstructure and mechanical properties in the hotrolled state, after reheating treatment at 950 ℃, its average grain sizes are apparently fine and the pearlite interlamellar spacing and lamellar cementite thickness coarsen to some extent, but both hardness and impact toughness increase to HRC 48 and 85 J, respectively. In the course of making spring, the optimum reheating austenitizing temperature for the 60Si2MnA steel is 950 ℃.
关键词:
austenitizing temperature;austenite grain;pearlite interlamellar spacing;hardness;toughness
B.W. Wang
,
H. Shen
金属学报(英文版)
Ni-Cr System solar selective thin solid films were prepared by d.c. magnetron reactivesputtering under the atmosphere of O2 and N2. Ni-Cr alloy was chosen as targetmaterial and copper sheets as substrate. Using SEM, Spectrophotometer and Talystepto analyze the relations between the selective characteristic and the structure, theformation and the thickness of the thin films. The aim is to obtain good solar selectivethin films with high absorptance and low emittance, which is applied to flat plate solarheat collectors.
关键词:
solar selective thin film
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