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Effect of Thread Helix Angle on the Axial Metal Flow of Cross Wedge Rolling Thread Shaft

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Effect of Thread Helix Angle on the Axial Metal Flow of Cros...

2013 International Conference on Advanced materials & Sports Equipment Design(AMSED 2013)

作者： Huajun Yan Lijuan Wang Yuzhong Liu Guochang Li Jinping Liu Zhenghuan Hu School of Materials Science and Engineering Hebei University of Science and Technology Hebei Key Laboratory of Material Near-net Forming Technology School of Management and Economics Hebei University of Science and Technology School of Mechanical Engineering University of Science and Technology Beijing

When rolling thread shaft in cross wedge rolling, forming quality of thread is affected by many process parameters such as the thread helix angle, which is a special and complex parameter. However, there is few study of the effect of the thread helix angle on thread shaft forming. In this paper how thread helix angle affects axial metal flow was analyzed from the perspective of rolling force and the forming process of thread shaft was simulated with different helix angles by the deform-3D software. Through the measurement of the point coordinates, the effect of the helix angle on the axial metal flow of rolled pieces was analyzed. Finally, the conclusion was obtained that helix angle causes the asymmetry of axial metal flow with small difference values for asymmetry and the axial metal flow of rolled pieces increases as the helix angle increases. The rolling thread segment can be ensured in the middle of rolled pieces by moving the blank a suitable distance in the reverse direction of the axial flow direction.

关键词： Cross wedge rolling Thread shafts Helix angle Metal flow

Effect of Solution and Aging Treatment on the Microstructure and Mechanical Properties of Al0.4cocrfeni Prepared by Laser-Powder Bed Fusion Using Al and Fecocrni Powders

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SSRN 2023年

作者： Zhu, Xiangjian Liu, Shan Wang, Xiebin Wang, Guangchun Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials Ministry of Education Shandong University Shandong Jinan250061 China Hebei Key Laboratory of Material Near-net Forming Technology Hebei University of Science and Technology Hebei Shijiazhuang050000 China

In this work, due to the insufficient diffusion of the phase forming element, which promotes the formation of the second phase, a dual phase Al0.4CoCrFeNi high entropy alloy (HEA) with BCC phase content of c.a. 13% and excellent mechanical properties was prepared by laser powder bed fusion (L-PBF) using AlSi10Mg and FeCoCrNi mixing powders. The effect of aging treatment, both with and without preceding solution treatment, on the microstructure and mechanical properties is addressed. Under direct aging, a large amount of nano σ and FCC phase are formed within the BCC phase, spherical L12 phase and dislocation cellular substructure coexist inside FCC grains. However, under solution-aging, the BCC phase is separated by newly generated FCC phase, and showing a sieve-like shape with the σ phase embedded into the phase boundary, the L12 phase is precipitated in a wave-like shape inside FCC grains without existence of dislocation. As a result, direct aging can improve rapidly the strength of the as-built alloy, but the plasticity decreases largely. On the contrary, solution-aging improves the strength while retaining considerable plasticity. Specifically, solution-aging treatment 1200℃/1 h+650℃/50 h simultaneously improves the strength and plasticity of the as-built alloy. And better yet, solution-aging sample 1200℃/1 h+650℃/100 h achieves a synergistic increase in strength and plasticity compared with all the direct aging samples. This work provides a new idea for the preparation of heterogeneous alloys with high second phase content with the low content of phase forming elements, and also provides guidance for the post-treatment performance regulation of dual phase HEAs. © 2023, The Authors. All rights reserved.

关键词： High-entropy alloys

Effect of Blank Shape and Size on the forming Quality of Thread Shaft Rolling in Cross Wedge Rolling

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Effect of Blank Shape and Size on the Forming Quality of Thr...

2013 International Conference on materials Science,Machinery and Energy Engineering(MSMEE 2013)

作者： Huajun Yan Haoen Mao Guochang Li Xiaoxi He Jinping Liu Zhenghuan Hu School of Materials Science and Engineering Hebei University of Science and Technology Hebei Key Laboratory of Material Near-net Forming Technology School of Management and Economics Hebei University of Science and Technology School of Mechanical Engineering University of Science and Technology Beijing

The defects of the lower tooth height and of larger pitch in thread portion of rolled pieces are prone to appearing when rolling thread shaft in cross wedge rollingTo solve this problem, changing the blank shape and size were triedTwo types of concave conical and round blanks are designed with concave conical blanks obtained by rolling in the cross wedge rollingBecause the design of the rolling die is simple, good precision of blank can be ensuredMultiple size types of blanks were designed and the rolling experiment was made in the rolling mill of model H630By measuring the values of the tooth height and pitch, the effect of blank shape on thread shafts rolled in the wedge rolling were investigated carefullyThe reasonable size range of the blank shape was obtainedThe conclusions above pave the theoretical foundation for the in-depth study on this technology.

关键词： Cross wedge rolling Thread shafts Round blank Concave cone Tooth height Pitch

Highly Oriented Microtube Arrays of Decagonal Quasicrystal Approximants in Al20si20mn20fe20ga20 High-Entropy Alloy

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SSRN 2023年

作者： He, Zhanbing Zhang, Tiantian Zhao, Liangqun Ma, Haikun Huang, Shuzhao Shen, Ningning Hui, Xidong State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing100083 China Hebei Key Laboratory of Material Near-Net Forming Technology School of Materials Science and Engineering Hebei University of Science and Technology Shijiazhuang050018 China

Micro- or nano-tubular materials have important applications due to their unique structure, while tubular quasicrystal-related structures are rarely found. Here, oriented microtube arrays of high-entropy decagonal quasicrystal (HE-DQC) approximants were prepared in Al20Si20Mn20Fe20Ga20 alloy by simple melt spinning. Transmission electron microscopy revealed microtubes mostly composed of alternating arrangements of (1/0, 2/1) quasicrystal approximant domains (lattice constants a = 0.73 nm, b = 1.23 nm, and c = 2.24 nm) and defective (1/0, 2/1) domains. However, high heat treatment leads to changes in the microtube morphology and structure. By nanoindentation testing, microtubes show hardness of 10.9 GPa and elastic modulus of 189.3 GPa. We demonstrate that the microtubes formation is mainly related to the temperature gradient caused by rapid solidification, twinning growth of approximant domains, and also the insufficient supply of raw materials in the later stages of solidification. © 2023, The Authors. All rights reserved.

关键词： Entropy

Enhancing microstructural properties of alumina ceramics via binary sintering aids

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Journal of Central South University 2021年第12期28卷 3705-3713页

作者： HU Yan-jun YIN Zi-qiang GONG Yu-bo YANG Zhi-gang YANG Zhan-ping LIANG Yin-chun DONG De-jun ZHAO Jin-jin School of Materials Science and Engineering Hebei Key Laboratory of Material Near Net Forming TechnologyHebei University of Science and TechnologyShijiazhuang 050018China School of Materials Science and Engineering Shijiazhuang Tiedao UniversityShijiazhuang 050043China Institute of Materials for Energy Conversion Shijiazhuang Tiedao UniversityShijiazhuang 050043China Nantong ZhuhaiKunming Cellulose Fibers Company Technical CenterNantong 226008China

Alumina ceramics are widely used in many fields such as cutting tools,laser shock materials,roadbed board and ***,Al_(2)O_(3)ceramics are prepared by a low-cost pressureless sintering technology,using the binary sintering aids of MgO and SiO_(2).The effects of sintering temperature and the ratio of binary sintering aids on the mechanical properties and microstructure of Al_(2)O_(3)ceramics are investigated.A spinel second phase(MgAl_(2)O_(4))is found out by the analysis of the results of XRD and EDS when MgO and SiO_(2)are introduced in the *** optimum properties are found when MgO content is 20 wt.%based on the total sintering aids and the sintering temperature is 1550℃.The bending strength and the bulk density reach a maximum value of 314 MPa and 3.73 g/cm^(3),*** addition of appropriate amount of SiO_(2)makes the formation of liquid phase sintering and the removal of large ***,a small amount of magnesium oxide doping has an effect on the grain refinement from the microstructure of the ***,it is believed that MgO and SiO_(2)are the ideal sintering aids for promoting the densification and property of alumina ceramics.

关键词： alumina ceramics binary sintering aids mechanical properties microstructure

Numerical simulation of Failure Behaviors of CFRP laminates on Hashin model coupled with cohesive elements

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Numerical simulation of Failure Behaviors of CFRP laminates ...

2018 International Conference on Advanced materials, Intelligent Manufacturing and Automation, AMIMA 2018

作者： Huang, Hongbo Ma, Xu Qiao, Jingwen Yanhong, Ding School of Material Science and Engineering Tianjin University of Technology Tianjin300384 China Tianjin Engineering Center of Near-Net-Shape Forming Technology for Metallic Materials Tianjin300384 China School of Electrical and Electronic Engineering Tianjin Key Laboratory of Film Electronic and Communication Devices Tianjin University of Technology Tianjin300384 China

The failure modes of carbon fiber reinforced composites (CFRP) was investigated in this study. A method of combination of Hashin model and cohesive elements was proposed to predict failure behaviors in T300/PR319 and AS carbon/epoxy laminates by FE model, while executing three-point bending test. The result shows that there are differences between the response of two materials during bending test. Fiber compression and matrix tension in T300/PR319 and AS carbon/epoxy appears first relatively. Subsequently delamination occurs in AS carbon/epoxy as a result of cohesive elements. A evaluating method of measuring fracture process displacement was also proposed under new damage criterion. © Published under licence by IOP Publishing Ltd.

关键词： Failure (mechanical)

Study on Wear Map and Wear Damage Mechanism of High Speed Steel

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SSRN 2023年

作者： Kang, Jie Liu, Yu Liang, Jingbin Wu, Dayong Li, Dong Ma, Haikun Su, Ru Hebei Key Laboratory of Material Near-net Forming Technology School of Materials Science and Engineering Hebei University of Science and Technology Hebei Shijiazhuang050000 China Key Laboratory of High Quality Mold Materials of Hebei Province Heye Science and Technology Co. Ltd. Hebei Shijiazhuang052165 China

In this study, the wear behavior of M42 high speed steel (HSS) cutting tools under different contact stress and sliding velocity conditions have been investigated to reveal the wear degradation and microstructural damage mechanisms. A wear map and damage mechanism map for M42 HSS have been established. Based on the magnitude of wear rates, the wear map can be divided into three regions: mild wear, medium wear, and severe wear. With increasing contact stress and sliding velocity, the damage mechanism of the high-speed steel undergoes a triple evolution: plowing with less micro-voids caused by minor small-sized carbide detachment, then slight delamination with more micro-voids and finally delamination with extensive micro-voids resulting from extensive large-sized carbide fracture and detachment. Diverse sizes of carbide spalling emerge as the primary driving factors behind both microstructure damage and wear performance deterioration in M42 HSS. Furthermore, a quantitative correlation between carbide spalling and wear rate has been established. Additionally, through linear regression analysis, contact stress exerts a relatively stronger influence on wear resistance of M42 HSS at room temperature compared to sliding velocity. © 2023, The Authors. All rights reserved.

关键词： Wear of materials

Mechanical Properties and Microstructure Revolution of Vibration Assisted Wire Arc Additive Manufacturing 2319 Aluminum Alloy

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SSRN 2023年

作者： Zhang, Liang Wang, Songtao Wang, Huixia Wang, Jun Bian, Wenzhuo Hebei Engineering Laboratory of Aviation Lightweight Composite Materials and Processing Technology School of Materials Science and Engineering Hebei University of Science and Technology Hebei050018 China Hebei Key Laboratory of Material Near-net Forming Technology School of Materials Science and Engineering Hebei University of Science and Technology Hebei050018 China Special-shaped Parts Forming Technology of Aviation Composites Laboratory of Hebei Province Hebei050018 China

In this study, a hybrid wire arc additive manufacturing (HWAAM) process that combines low frequency vibration with cold metal transfer (CMT) arc is proposed to address the problems of porosity, coarse grains, and low mechanical performance encountered in WAAM aluminum alloys. The effects of different vibration frequencies on the microstructure and mechanical properties were investigated. The results indicated that as the vibration frequency increases, the grain size refinement reaches a maximum of 19.1% compared with the non-vibrated specimen. Vibration can enhance the fluidity and the cooling rate of the weld pool. The fatigue fracture of dendrite arms is the main mechanism of microstructure grain refinement caused by vibration. The dynamic bending stress induced by vibration on the dendrite arms and the root remelting phenomenon are the dominant factors for the dendrite fragmentation. Increasing the vibration frequency did not result in an obvious improvement in the tensile strength of the specimens, but did significantly increase the elongation. With the increase in vibration frequency, the maximum transverse and longitudinal elongation reached 22.2% and 23.5% respectively, a raise of 15.6% and 38.2% compared with non-vibrated specimen. Vibration reduced the size and distribution density of pores on the fracture surface, and increased the dimpled microstructure, improving the mechanical performance of the aluminum alloy. © 2023, The Authors. All rights reserved.

关键词： 3D printing

A New Method for Improving Static and High Frequency Magnetic Properties of Fe67Co18Si11B4Amorphous Alloy 10

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A New Method for Improving Static and High Frequency Magneti...

2023 10th International Conference on Advanced Manufacturing technology and materials Engineering, AMTME 2023

作者： Wang, Dongmeng Ding, Yanhong Ma, Xu Li, Yan School of Integrated Circuit Science and Engineering Tianjin Key Laboratory of Film Electronic and Communication Devices Tianjin University of Technology Tianjin300384 China School of Material Science and Engineering Tianjin Engineering Center of Near-Net-Shape Forming Technology for Metallic Materials Tianjin University of Technology Tianjin300384 China Co. Ltd Tianjin300385 China

Rapidly quenched ribbons with a composition of Fe67Co18Si11B4 have been investigated. Surface leveling on the ribbon-free surface leads to the decline of the interior stress of Fe67Co18Si11B4 amorphous alloy, making a decrease of coercivity and a great improvement of static magnetic properties. Free surface leveling treatment can improve the AC magnetic properties of the Fe67Co18Si11B4 amorphous alloy. In high frequency region 106 Hz 3 can be achieved after surface leveling. Free surface leveling is an attractive method to achieve improvements in both static and high frequency magnetic properties. © Published under licence by IOP Publishing Ltd.

关键词： Cobalt alloys