Search

Your search keyword '"Cheng, Xiaonong"' showing total 544 results
Start Over Author "Cheng, Xiaonong"
544 results on '"Cheng, Xiaonong"'

1. Effects of LB/M Duplex Phase Heat Treatment on Microstructure and Mechanical Properties of Cold Working Die Steel DC53

Author

Yuan Zhizhong, Chen Lu, Zhang Bocheng, Liu Haiming, Niu Zongran , Wang Zhiyuan, Ju Yulin, Cheng Xiaonong

Subjects
cold working die steel； dc53； heat treatment； microstructure； mechanical property, Materials of engineering and construction. Mechanics of materials, TA401-492, Technology
Abstract

The effects of Quenching-Tempering-Austempering （QTA） duplex phase heat treatment process （Q 1 030 ℃， 30 min； T 520 ℃， 2 h； A 250 ℃， 3 h） at different prequenching temperatures on the microstructure， mechanical properties and the friction and wear properties of cold working die steel DC53 were investigated and the results were compared with those of the conventional Quenching-Tempering （QT） heat treatment process （Q 1 030 ℃， 30 min； T 520 ℃， 2 h）. The results show that the microstructure obtained by QT process is mainly tempered martensite and the microstructure mainly composing Lower Bainite/Martensite （LB/M） duplex phase can be resulted from the QTA process. The strength reduction due to the LB and the retained austenite （AR） can be partly offset by the grain refinement strengthening from the refinement of original austenite grain by duplex phases， and the impact toughness of DC53 can be greatly improved by this complex microstructure. Compared with the mechanical properties of the QT process， the hardness of the QTA at prequenching temperature 100 ℃ is only 1.4 HRC lower but the impact absorption energy is 2.44 times higher. Therefore， superior combination of strength and toughness can be obtained by the QTA process.

Published
2024
Full Text
View/download PDF

35. Investigation of constitutive model of as-extruded spray-forming 7055 aluminum alloy based on BP artificial neural network

Author

LUO Rui, CAO Yun, QIU Yu, CUI Shugang, ZHOU Haotian, ZHOU Yiming, YUAN Fei, ZHANG Xiaopeipei, and CHENG Xiaonong

Subjects
spray forming, 7055 aluminum alloy, constitutive model, neural network, hot deformation, Motor vehicles. Aeronautics. Astronautics, TL1-4050
Abstract

Gleeble physical simulation technique was employed to investigate the high-temperature flow stress characteristics of the studied spray forming 7055 aluminum alloy. Simultaneously, the Arrhenius constitutive model which couples the parameter of true strain and the BP artificial neural network constitutive model were contrastingly utilized to predict the flow stress behavior of the experimental alloy. The result shows that the flow stress of spray forming 7075 aluminum alloy is significantly affected by deformation parameter, which is negative correlated with deformation temperature and positively correlated with strain rate. Through the comparison of the two models, the average relative error of the Arrhenius constitutive model lies over 2%. And the error of the model tends to increase with the rising temperature. Moreover, the average absolute error and the average relative error reach the maximum at hot processing temperature (around 450 ℃). It is difficult to precisely predict the flow stress characteristics of the alloy. However, BP artificial neural network constitutive model has higher prediction accuracy, the average relative error δ value is only 0.813% and has higher temperature stability.

Published
2021
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results