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Effect of direct aging heat treatment on microstructures and properties of CuCrZr alloy manufactured by laser powder bed fusion

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Journal of Materials Research and technology 2025年 36卷 8591-8601页

作者： Runze Zhang Junyan Fang Yongming Guo Huaixue Li Lei Shi Peng Liu School of Materials Science and Engineering Shandong Jianzhu University Jinan 250101 PR China Shandong Tianrunzc Additive Manufacturing Co. LTD Weihai 264404 PR China Science and Technology on Power Beam Processes Laboratory AVIC Manufacturing Technology Institute Beijing 100024 PR China

Effect of heat treatment on the microstructures and properties of CuCrZr alloy fabricated by laser powder bed fusion (LPBF) were investigated using OM, SEM, EBSD, TEM and electrochemical tests. However, due to the significant non-equilibrium solidification process during LPBF, residual stress and microstructural inhomogeneity are prone to occur in the alloy. This paper employed a direct aging heat treatment (DAHT) process (475 °C+90min) to induce recrystallization and precipitation of strengthening phases, thereby improving the properties of alloys. The results showed that the grain size of the alloy was significantly reduced, with the XOY plane being 49.8um and the XOZ plane being 96.5um. The proportion of high-angle grain boundaries (HAGBs) also increased significantly, with the HAGB proportions in the XOY and XOZ planes being 76.3 % and 76.5 %, respectively. The dislocation density and strain level of the alloy were also reduced, with the KAM values of the XOY and XOZ planes both dropping to 0.32, and the dislocation densities decreasing to 2.19 × 10 13 m −2 and 2.11 × 10 13 m −2 , respectively. Meanwhile, a large number of nano-scale Cr-rich precipitates were present at the grain boundaries and within the grains. The hardness of the alloy increased by about 75 %, and its corrosion resistance was also significantly enhanced, with the highest corrosion potential being −128.6 mV and the lowest corrosion current density being 1.40 × 10 −5 A/cm 2 . Therefore, the DAHT process can enhance the properties of LPBF-fabricated CuCrZr alloy, providing an important research basis for the preparation of high-performance copper alloys using LPBF technology and their wider application.

关键词： LPBF CuCrZr alloy Heat treatment Microstructures Mechanical properties Corrosion resistance

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Simulation research of thermionic emission process and impact of voltage parameters in the three-pole electron gun

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Results in Physics 2025年 70卷

作者： Hu, Haoyang Zhao, Yue Shang, Pengcheng Zhang, Feibin Wu, Aiping Zhao, Haiyan Li, Lihang State Key Laboratory of Clean and Efficient Turbomachinery Power Equipment Department of Mechanical Engineering Tsinghua University Beijing 100084 China Key Laboratory for Advanced Materials Processing Technology Ministry of Education Beijing 100084 China Department of Mechanical Engineering Tsinghua University Beijing 100084 China State Key Laboratory of Tribology in Advanced Equipment Tsinghua University Beijing 100084 China Science and Technology on Power Beam Processes Laboratory AVIC Manufacturing Technology Institute Beijing 100024 China

The three-pole electron gun is composed of cathode, anode and grid electrode, which can effectively control the emission beam current and is widely used in welding and additive manufacturing equipment. However, the characteristics of the emission beam and the process of beam control have yet to be fully and accurately elucidated. Considering that the characteristics of the electron beam at the emission stage have a significant effect on the beam quality, the electric field distribution and electron beam trajectory at the emission stage are studied based on the simulation method of bidirectionally coupled particle tracing. The results show that a spatial potential barrier several tens of microns high is formed on the cathode surface. The different relative potential across the barrier at different positions leads to the non-uniform effective emission beam density of the cathode. With the increase of bias voltage, the effective emission area and emission beam density decrease simultaneously. The average emission beam density varies with the accelerating voltage, which does not follow the Child-Langmuir law, but exhibits a more significant trend of variation. The present work proposes a modified formula suitable for the three-pole electron gun for calculating the average emission beam density, obtaining good fitting results. © 2025

关键词： beam emission Numerical simulations Potential barrier Process parameters Three-pole electron gun

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Investigation of Surface Integrity on TC17 Titanium Alloy Treated by Square-spot Laser Shock Peening

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Chinese Journal of Aeronautics 2012年第4期25卷 650-656页

作者： CAO Ziwen XU Haiying ZOU Shikun CHE Zhigang National Key Laboratory of Science and Technology on Power Beam Processes Beijing Aeronautical Manufacturing Technology Research instituteBeijing 100024China

Laser shock peening（LSP） is an innovative surface treatment method,which has been shown to greatly improve the fatigue life of many metallic *** work investigates surface integrity of TC17 titanium alloy treated by LSP with innovative square laser ***：glass laser with duration of 30 ns and spot size of 4 mm×4 mm is *** surface morphology and surface residual stress of the TC17 titanium alloy,treated with varying peening parameters such as laser power density and overlapping ratio,have been studied in *** results show that laser pulse energy greatly influences surface morphology and surface residual stress around single-spot treated areas,and compressive residual stresses are saturated as laser pulse energy is over 55 *** are significantly different surface morphologies and residual stress distributions at the overlapped areas with different overlapping ratios.A relative smooth surface is produced with uniform compressive residual stress distribution at an overlapping ratio of 8 %.The experiment of residual stress relaxation is implemented by measuring residual stress at the center of four overlapped spots and by four point bending fatigue test at the frequency of 105 *** compressive residual stresses induced by LSP are found to relax quite slowly under cyclic fatigue loading.

关键词： laser shock peening square laser spot residual stresses titanium alloy shock wave

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Preparation and characterization of thick cubic boron nitride films

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Chinese Physics B 2014年第6期23卷 462-467页

作者：王明娥马国佳董闯巩水利 School of Material and Engineering Dalian University of Technology National Key Laboratory of Science and Technology on Power Beam Processes Beijing Aeronautical Manufacturing Technology Research Institute

Cubic boron nitride （c-BN） films are prepared by the radio frequency magnetron sputtering technique. The stresses and crystallinities of the films are estimated by the Fourier transform infrared spectroscopy of c-BN samples, including the peak shifts and varieties of full widths at half maximum. The effects of the B-C-N interlayer and the two-stage deposition method on the c-BN films are investigated. Then the thick and stable c-BN films are prepared by a combination of the two methods. The properties of the interlayer and film are also characterized.

关键词： cubic BN films B-C-N interlayer stress hardness

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Influences of nitrogen flow rate on the structures and properties of Ti and N co-doped diamond-like carbon films deposited by arc ion plating

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Chinese Physics B 2014年第4期23卷 616-621页

作者：张林马国佳林国强马贺韩克昌 Key Laboratory for Material Modification by Laser Ion and Electron Beams Dalian University of Technology Science and Technology on Power Beam Processes Laboratory Beijing Aeronautical Manufacturing Technology Research Institute

In this paper, Ti-C-N nanocomposite films are deposited under different nitrogen flow rates by pulsed bias arc ion plating using Ti and graphite targets in the Ar/N2 mixture gas. The surface morphologies, compositions, microstructures, and mechanical properties of the Ti-C-N films are investigated systematically by field emission scanning electron mi- croscopy （FE-SEM）, x-ray photoelectron spectroscopy （XPS）, grazing incident x-ray diffraction （GIXRD）, Raman spectra, and nano-indentation. The results show that the nanocrystalline Ti（C,N） phase precipitates in the film from GIXRD and XPS analysis, and Raman spectra prove the presence of diamond-like carbon, indicating the formation of nanocomposite film with microstructures comprising nanocrystalline Ti（C,N） phase embedded into a diamond-like matrix. The nitrogen flow rate has a significant effect on the composition, structure, and properties of the film. The nano-hardness and elastic modulus first increase and then decrease as nitrogen flow rate increases, reaching a maximum of 34.3 GPa and 383.2 GPa, at a nitrogen flow rate of 90 sccm, respectively.

关键词： arc ion plating Ti-C-N film nitrogen flow rate microstructure

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Microstructures and fatigue properties of electron beam welds with beam oscillation for heavy section TC4-DT alloy

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Chinese Journal of Aeronautics 2014年第4期27卷 1015-1021页

作者： Fu Pengfei Mao Zhiyong Zuo Congjin Wang Yajun Wang Chunming College of Materials Science and Engineering Huazhong University of Science and Technology Science and Technology on Power Beam Processes Laboratory Beijing Aeronautical Manufacturing Technology Research Institute Institute of Mechanical Engineering and Automation Beihang University

With the development of the manufacturing technology, electron beam welding（EBW） is capable of producing titanium alloy large parts in aero fields. To increase the applications and improve the properties, EBW with beam oscillation was investigated on TC4-DT alloy with50 mm thickness. We detected the welding samples by X-ray NDT, observed the microstructures of the welds, and tested the fatigue properties of the joints. The results showed that EBW with beam oscillation improved the weld morphology as well as welding quality, and the microstructure homogeneity of the welds and HAZ along the weld penetration were also improved. The fatigue properties of the joints with beam oscillation were more excellent than those of conventional EBW, even equal to those of the base metal under high stresses. The influences of the processing and the microstructure on the properties with beam oscillation were discussed.

关键词： beam oscillation Electron beam welding(EBW) Fatigue Microstructure Titanium alloy

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Effect of Base Material on Microstructure and Texture Evolution of a Ti–6Al–4V Electron-beam Welded Joint

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Acta Metallurgica Sinica(English Letters) 2017年第5期30卷 499-504页

作者： G.Q.Wang Z.B.Zhao B.B.Yu J.R.Liu Q.J.Wang J.H.Zhang R.Yang J.W.Li School of Materials Science and Engineering University of Science and Technology of China Institute of Metal Research Chinese Academy of Sciences Science and Technology on Power Beam Processes Laboratory Beijing Aeronautical Manufacturing Technology Research Institute

The effect of base material（BM） on microstructure and crystallographic orientation evolution of a Ti–6Al–4V electron-beam welded joint was investigated. Meanwhile, the crystallographic orientation of prior b grains was studied by advanced electron backscattered diffraction data processing. The inhomogeneity of microstructure within welded joint was formed due to the different microstructures of BM. By comparing microstructure details of the welded joint, including microstructure morphology and crystallographic orientation with those of the base material, it can be found that both the microstructure morphology and crystallographic orientation of the EBW joint would be controlled by BM.

关键词： Electron-beam welding Titanium alloys Prior b orientation Microstructure Texture

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Calculation of vaporization pressure in laser penetration welding of 304 stainless steel

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China Welding 2010年第2期19卷 42-46页

作者：段爱琴张朴陈俐 National Key Laboratory of Science and Technology on Power Beam Processes Beijing Aeronautical Manufacturing Research Institute Beijing 100024.

Many research results have revealed that vaporization pressure has important effects on the formation of the keyhole and molten pool during laser welding. In this paper, based on law of conservation of energy, an innovative physical model is found to calculate the vaporization pressure during laser welding. In this model, vaporization pressure can be calculated according to some characteristics of the spatter particle. These features include the size, velocity and displacement. They can be measured through images taken by high-speed camera. The periods of this pressure also measured by counting opening and closing time of the bottom keyholes. At this welding condition, the typical vaporization pressure is about 20 203 Pa and the period is about 6. 9 ms. The average opening time of bottom keyholes is about 4. 3 ms, and the closing time is about 2. 6 ms.

关键词： laser welding keyhole vaporization pressure opening and closing time

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Characteristics of keyhole and molten pool during laser welding of TC4 Tialloy 36

Characteristics of keyhole and molten pool during laser weld...

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36th International MATADOR Conference

作者： Aiqin, Duan Li, Chen BAMTRI National Key Laboratory of Science and Technology on Power Beam Processes Beijing China

ISBN: (纸本)9781849964326

In this paper, the characteristics of keyhole and molten pool during laser welding of TC4 have been studied through measuring its images. The study shows that the size of keyholes in all processes almost keep constant. This means that there is a quite steady absorption for laser energy in all welding processes of TC4, and this stability almost is not affected by welding parameters. Because of this steady energy input, the steady molten pool would be formed in all quasi-stationary processes, and it is verified by images of molten pool at different time. The results at different heat input clearly show that the area of different temperature rises with the increase of the heat input. The length of molten pool also increases with the heat input. But the heat input has less influence on the width than others.

关键词： Laser beam welding

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The influence of the pressure of Ar shielding gas on the keyhole behavior during CO2 laser welding of TA15

The influence of the pressure of Ar shielding gas on the key...

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31st International Congress on Applications of Lasers and Electro-Optics, ICALEO 2012

作者： Aiqin, Duan Shuili, Gong Song, Huang National Key Laboratory of Science and Technology on Power Beam Processes BAMTRI Beijing China

Many studies have shown that during laser welding, shielding gases play a key role in protecting the welding area from the surrounding air, and have great effects on energy absorption, keyhole formation, temperature field distribution and so on. Because of these causes, it could finally have some effects on geometry and defect of welds, especially for weld material like Ti-alloy. In the practices, it is found that not only the different gas has great influence on the welding results;the pressure also has great influence. In this paper, a series of experiments about CO2 laser welding of TA15 TI-alloy were completed by using Ar as shielding gas at different gas pressure. At the welding processes, the images of vapor/plasma were captured by the high-speed camera. The results show that the pressure of shielding gas has very important influence on geometries of welds to TA15 Ti-alloy. Analyzing the images of vapor/plasma, it is found that the different pressure can change the keyhole behavior. Especially it can change the results of vapor/plasmas erupting from the keyhole of back weld, Furthermore, it is found that at different gas pressures, the recoil pressures in the keyhole are quite different. And it is the reason that the pressure influences the welds.

关键词： Laser beam welding

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