| 1 | Intermetallic Compounds in the Banded Structure and Their Effect on Mechanical Properties of Al/Mg Dissimilar Friction Stir Welding Joints显示文摘Dissimilar friction stir welding(FSW) between aluminum and magnesium alloy was performed, using various tool rotational speed(TRS) at a ?xed travel speed, with tool offset to aluminum to investigate the formation of intermetallic compounds(IMCs) in the banded structure(BS) zone and their effect on mechanical properties. Large quantities of IMCs, in the form of alternating bands of particles or lamellae, were found in the BS zone, where drastic material intermixing occurred during FSW. The BS microstructural characters in terms of the morphology of the bands and the quantity and distribution of IMC particles varied with TRS. All welds exhibited brittle fracture mode with their fracture paths propagating mainly in/along the IMCs in the BS. It is shown that these BS microstructural characters have signi?cant effect on the mechanical properties of the joints. Suggestions on tailoring the BS microstructure were proposed for improving the strength of the BS zone and the ?nal mechanical properties of the Al/Mg FSW joints. | Hui Shi Ke Chen Zhiyuan Liang Fengbo Dong Taiwu Yu Xianping Dong Lanting Zhang Aidang Shan | 2017 | Journal of Materials Science & Technology2017，33，4： | 8 |
| 2 | Component analysis and risk assessment of biogas slurry from biogas plants显示文摘Massive amounts of biogas slurry are produced due to the development of biogas plants.The pollution features and the risk of biogas slurry were fully evaluated in this work.Thirty-one biogas slurry samples were collected from sixteen different cities and five different raw materials biogas plants(e.g.cattle manure,swine manure,straw-manure mixture,kitchen waste and chicken manure).The chemical oxygen demand(COD),ammonia nitrogen(NH_(4)^(+)-N),anions(e.g.Cl^(-1),SO_(4)^(2-),NO_(3)^(-)and PO_(4)^(3-)),antibiotics(e.g.sulphonamides,quinolones,β2-receptor agonists,macrolides,tetracyclines and crystal violet)and heavy metals(e.g.Cu,Cd,As,Cr,Hg,Zn and Pb)contents from these biogas slurry samples were systematically investigated.On this basis,risk assessment of biogas slurry was also performed.The concentrations of COD,NH_(4)^(+)-N and PO_(4)^(3-) in biogas slurry samples with chicken manure as raw material were significantly higher than those of other raw materials.Therefore,the biogas slurry from chicken manure raw material demonstrated the most serious eutrophication threat.The antibiotic contents in biogas slurry samples from swine manure were the highest among five raw materials,mostly sulphonamides,quinolones and tetracyclines.Biogas slurry revealed particularly serious arsenic contamination and moderate potential ecological risk.The quadratic polynomial stepwise regression model can quantitatively describe the correlation among NH_(4)^(+)-N,PO_(4)^(3+) and heavy metals concentration of biogas slurry.This work demonstrated a universal potential threat from biogas slurry that can provide supporting data and theoretical basis for harmless treatment and reuse of biogas slurry. | Lanting Ke Xiaobin Liu Bingqing Du Yuanpeng Wang Yanmei Zheng Qingbiao Li | 2022 | Chinese Journal of Chemical Engineering2022，35，4： | 5 |
| 3 | Inhibition of Abnormal Grain Growth in Stir Zone via In‑Situ Intermetallic Particle Formation During Friction Stir Welding of AA6061显示文摘Abnormal grain growth(AGG)has been widely observed in many friction stir welded(FSWed)joints during post-weld heat treatment(PWHT).The coarse grain structure not only reduces the strength of the joint but also limits its usage in superplastic forming.Several methods have been reported in previous studies to inhibit AGG,but all of them can only mitigate AGG.Complete inhibition of AGG was not achieved.In the current research,AGG was widely observed during the PWHT of friction stir welded AA6061.Multi-pass FSW enhanced the thermal stability of the as-welded grain structure but did not eliminate the occurrence of AGG.A new welding method was developed with the ball-milled Al–Ti powder mixture introduced into the stir zone and proved effective in inhibiting AGG in FSWed AA6061 during PWHT.The adoption of 5-pass FSW with an alternate rotation mode succeeded in producing an AGG-free sample.Microscopic characterizations conducted in the stir zone showed an evolution of Al–Ti powder mixture into different particle formations and Al3Ti new phase.Quantitative analysis of the second phase particles(SPPs)in the stir zone confirmed the increases in both particle number and average size.The quantitative results fit well with Humphreys’grain growth model,which theoretically explains the mechanism for AGG inhibition,i.e.,the significantly enhanced particle pinning effect. | Xin Zou Cunli Liu Muyang Deng Ji Chen Lanting Zhang Ke Chen | 2023 | Acta Metallurgica Sinica(English Letters)2023，36，4： | 0 |
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