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Mathematical analysis and its experimental comparisons for the accumulative roll bonding(ARB)process with different superimposed layers

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Journal of Magnesium and Alloys 2021年第5期9卷 1761-1772页

作者： Haipeng Zheng Ruizhi Wu Legan Hou Jinghuai Zhang Milin Zhang Key Laboratory of Superlight Materials and Surface Technology Ministry of EducationHarbin Engineering UniversityNo.145 Nantong Street Nangang DistrictHarbin 150001China College of Science Heihe UniversityHeihe 164300PR China

Based on the traditional two-layer accumulative roll bonding(TARB),the geometrical variations and mathematical relationship during the four-layer accumulative roll bonding(FARB)were derived and ***,the multi-layer accumulative roll bonding(MARB)technology was proposed and the geometrical variations and mathematical relationship of MARB were simultaneously derived and ***,Mg-14Li-3Al-2Gd(LAGd1432)sheets were fabricated by TARB and FARB,*** with the TARB,the FARB has a higher accumulative efficiency in terms of accumulative layers,total number of interfaces,interface spacing,total deformation and equivalent ***,the FARB-processed sheets in lower cycles have the similar microstructure and mechanical properties of the TARB-processed sheets in higher *** addition,FARB process can further break through the deformation limit of TARB process in a single cycle through adopting two-step rolling in one cycle with 50%deformation in one pass and 75%accumulative deformation in one cycle,which can effectively solve the problem of poor interface bonding of the latest interface brought by the last cycle,and thus significantly improve the phenomenon of unstable performance of the ARB-processed sheets.

关键词： ARB Mathematical relationship equivalent strain Strengthening mechanism

Relationship between Hardness and Deformation during Cold Rolling Process of Complex Profles

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Chinese Journal of Mechanical Engineering 2023年第5期36卷 315-329页

作者： Dawei Zhang Linghao Hu Bingkun Liu Shengdun Zhao Xi’an Key Laboratory of Intelligent Equipment and Control School of Mechanical EngineeringXi’an Jiaotong UniversityXi’an 710049China

The hardening on surface of complex profles such as thread and spline manufactured by cold rolling can efectively improve the mechanical properties and surface quality of rolled parts. The distribution of hardness in superfcial layer is closely related to the deformation by rolling. To establish the suitable correlation model for describing the relationship between strain and hardness during cold rolling forming process of complex profles is helpful to the optimization of rolling parameters and improvement of rolling process. In this study, a physical analog experiment refecting the uneven deformation during complex-profle rolling process has been extracted and designed, and then the large date set (more than 400 data points) of training samples refecting the local deformation characteristics of complexprofle rolling have been obtained. Several types of polynomials and power functions were adopted in regression analysis, and the regression correlation models of 45# steel were evaluated by the single-pass and multi-pass physical analog experiments and the complex-profle rolling experiment. The results indicated that the predicting accuracy of polynomial regression model is better in the strain range (i.e., ε strain and hardness out strain range (i.e., ε > 1.2) of training samples can be well described by power regression model;so the correlation relationship between strain and hardness during complex-profle rolling process of 45# steel can be characterized by a segmented function such as third-order polynomial in the range ε 1.2;and the predicting error of the regression model by segmented function is less than 10%.

关键词： Complex profle Cold rolling Multi passes equivalent strain Vickers hardness

Effect of Fe Particle on the Surface Peeling in Cu-Fe-P Lead Frame

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Journal of Wuhan University of Technology(Materials Science) 2006年第3期21卷 18-20页

作者：苏娟华 College of Materials Science and Engineering Henan University of Science and Technology Luoyang 471003ChinaCollege of Materials Science and Engineering Northwestern Polytechnical University Xi'an 710072China

Under the surface peeling of Cu- Fe- P lead frame alloy larger Fe particles were observed by energy dispersive spectroscopy. By using the large strain two-dinension plane strain model and elastic plastic finite element method, the cause for peeling damage of Cu-Fe-P lead frame aUoy was investigated. The results show that when the content of Fe particles is more than 30% at local Fe-rich area the intense stress coacentration in the Fe particle would make the Fe particle broken up. The high equivalent stress mutation and the mismatch of equivalent strain 10% at the two sides of intefrace make it easy to develop the crack and peeling damage on finish rolling. The larger Fe particles in the Cu-Fe-P alloy should be avoided.

关键词： Cu-Fe-P lead frame surface peeling equivalent Stress equivalent strain