Zhenjun ZHOU
,
Zhiguo XIAO
,
Wei PAN
,
Zhipeng XIE
,
Xixian LUO
,
Lei JIN
材料科学技术（英文）
Concrete containing short carbon-coated-nylon fibers (0.4~2.0 vol. pct) exhibited quasi-ductile response by developing a large damage zone prior to fracture localization. In the damage zone, the material was microcracked but continued to local strain-harden. The carbon-coated-nylon-fiber-reinforced concrete composites (NFRC) were found to be an intrinsically smart concrete that could sense elastic and inelastic deformation, as well as fracture. The fibers served to bridge the cracks and the carbon coating gave the conduction path. The signal provided came from the change in electrical resistance, which was reversible for elastic deformation and irreversible for inelastic deformation and fracture. The resistance decrease was due to the reduction of surface touch resistance between fiber and matrix and the crack closure. The resistance irreversible increase resulted from the crack opening and breakage of the carbon coating on nylon fiber.
关键词:
Concrete
,
null
,
null
,
null
Yourong XU
,
Liangsheng CHEN
,
Deying WANG
,
Lei JIN
材料科学技术（英文）
The mechanical behaviors of high Mo austenitic stainless steel 00Cr20Ni18Mo6Cu[N] have been investigated using the methods of hot compression simulation test on the Thermecmaster-Z simulator. The dynamic recrystallization kinetic equation was established, Avrami coefficient n lies in between 0.9 similar to 2 depending on deformation parameters. A perfect flow stress model considering dynamic recrystallization was also established. Dynamic recrystallization tends to complete at 1050℃ and high strain rate, but at temperature below 950℃, it is hard to occur. Double-stage interrupt compression tests were carried out. Activation energy for static and metadynamic recrystallization have been obtained respectively (Q(SRX)=483.7, Q(MDRX)=253.5 kJ/mol). Avrami coefficient of MDRX is about 0.5, and t(0.5)-kinetics equations of SRX and MDRX have also been constructed. The evolution of microstructures during interrupt compression deformation was investigated. Static and metadynamic recrystallization is essential to improve plasticity, at temperature above 1000℃ increasing interpass time has advantage for static and metadynamic recrystallization.
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