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镀铝对CoCrNiAlY-YSZ-LaMgAl_(11)O_(19)双陶瓷热障涂层高温抗氧化行为的影响
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作者 解志文 陶浩天 +3 位作者 刘天新 陈永君 胡素影 马北一 《航空制造技术》 CSCD 北大核心 2024年第4期58-63,共6页
采用电弧离子镀(AIP)技术在CoCrNiAlY-YSZ-LaMA双陶瓷涂层表面沉积一层Al镀层,利用XRD、SEM和EDS等微尺度分析表征方法,全面解析涂层在大气暴露过程中的高温氧化行为。研究结果表明,未镀铝LaMA层在氧化过程中发生严重体积收缩,导致纵向... 采用电弧离子镀(AIP)技术在CoCrNiAlY-YSZ-LaMA双陶瓷涂层表面沉积一层Al镀层,利用XRD、SEM和EDS等微尺度分析表征方法,全面解析涂层在大气暴露过程中的高温氧化行为。研究结果表明,未镀铝LaMA层在氧化过程中发生严重体积收缩,导致纵向微裂纹萌生和扩展。这些微裂纹成为氧气向内部扩散的通道,导致涂层呈现持续氧化增重趋势、TGO快速生长和严重的元素扩散,并最终加剧涂层断裂失效。但镀铝涂层样品表现出更好的高温抗氧化性能与结构稳定性,高温氧化过程中,表面Al镀层与氧气发生原位反应生成致密Al2O3屏障层,有效阻止或延迟氧气内部渗透,使TGO缓慢生长,其氧化增重从20h时的8.59mg/cm^(2)略微上升到80h时的9.46mg/cm^(2)。本研究结果为双陶瓷热障涂层的延寿设计与界面热生长应力调控开辟出全新技术途径和理论视野。 展开更多
关键词 双陶瓷热障涂层 al镀层 高温抗氧化性能 热生长氧化物(TGO) 结构稳定性
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重熔对Al-Ti-La中间合金中Ti_(2)Al_(20)La相的影响
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作者 丁万武 田旭东 +4 位作者 陈建超 安家志 余海存 魏振鹏 杨成亮 《有色金属工程》 CAS 北大核心 2024年第8期56-66,共11页
通过扫描电镜、X射线衍射和电子探针等分析研究了重熔过程中不同保温时间和温度对Al-Ti-La中间合金中Ti_(2)Al_(20)La相的含量、形态尺寸和稳定性的影响。结果表明:在750℃下,随着保温时间的延长,Ti_(2)Al_(20)La相的溶解度逐渐增大,含... 通过扫描电镜、X射线衍射和电子探针等分析研究了重熔过程中不同保温时间和温度对Al-Ti-La中间合金中Ti_(2)Al_(20)La相的含量、形态尺寸和稳定性的影响。结果表明:在750℃下,随着保温时间的延长,Ti_(2)Al_(20)La相的溶解度逐渐增大,含量由未处理的20.776%下降至13.72%,形态由块状演变为圆整和细小的片状,长宽比由2.33下降至1.52;在1000℃下,保温15 min后溶解度较大,含量降低至4.5%,形态演变为尖锐的长条状,长宽比上升至2.55;溶解产生的La原子与Al在晶界处形成La-Al金属间化合物(IMC),Ti原子在基体中的分布密度随保温时间的延长和保温温度的升高而增高,以游离态均匀分布在基体中。 展开更多
关键词 al-Ti-la合金 Ti_(2)al_(20)la 重熔 保温时间
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微量稀土La对Al-7%Si-0.6%Fe合金组织与性能的影响 被引量:2
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作者 戚忠乙 王博 +2 位作者 江鸿翔 张丽丽 何杰 《物理学报》 SCIE EI CAS CSCD 北大核心 2024年第7期281-291,共11页
在Al(铝)-Si(硅)合金中同时添加Sr(锶)和B(硼)存在“中毒”现象,无法同时细化α-Al晶粒和变质共晶Si.本文研究了在同时添加α-Al晶粒细化剂B和共晶Si变质剂Sr的条件下,微量稀土La(镧)对Al-7%Si-0.6%Fe合金组织、热导率和力学性能的影响... 在Al(铝)-Si(硅)合金中同时添加Sr(锶)和B(硼)存在“中毒”现象,无法同时细化α-Al晶粒和变质共晶Si.本文研究了在同时添加α-Al晶粒细化剂B和共晶Si变质剂Sr的条件下,微量稀土La(镧)对Al-7%Si-0.6%Fe合金组织、热导率和力学性能的影响,分析了稀土La的影响规律及其作用机理.结果表明微量稀土La的添加,一方面可以中和Sr与B的毒化效应,提升共晶Si的变质效果;另一方面可以促使α-Al异质形核基底La B6的形成,并作为表面活性剂降低α-Al的形核过冷度,从而细化α-Al晶粒.共晶Si的变质以及α-Al晶粒的细化有助于同时提升Al-7%Si-0.6%Fe合金的热导率及力学性能.此外,当稀土La的添加量在0.02%—0.06%之间时,合金的导热性能明显提升;随着La添加量的进一步增大,合金热导率下降. 展开更多
关键词 al-SI合金 微合金化la 凝固组织 热导率
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水稻乙酰乳酸合酶Ala179Val突变赋予ALS抑制剂类除草剂广谱抗性
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作者 安晨 韶也 +2 位作者 彭彦 毛毕刚 赵炳然 《植物遗传资源学报》 CAS CSCD 北大核心 2024年第2期259-269,共11页
为了鉴定新型水稻突变体ALS179对乙酰乳酸合酶(ALS,acetolactate synthase)抑制剂类除草剂的抗性,本研究以野生型水稻华航31(HH31)、耐咪唑啉酮除草剂水稻ALS627突变体和甲基磺酸乙酯(EMS,ethyl methyl sulfone)诱变的新型水稻突变体ALS... 为了鉴定新型水稻突变体ALS179对乙酰乳酸合酶(ALS,acetolactate synthase)抑制剂类除草剂的抗性,本研究以野生型水稻华航31(HH31)、耐咪唑啉酮除草剂水稻ALS627突变体和甲基磺酸乙酯(EMS,ethyl methyl sulfone)诱变的新型水稻突变体ALS179为试验材料,通过不同浓度下的4类乙酰乳酸合酶抑制剂类除草剂包衣浸种和苗期喷施处理,进一步测定表型及相关酶活性指标来探究突变体ALS179的抗性。结果表明,经过除草剂包衣浸种以及苗期喷施处理后,突变体ALS179对苯磺隆、咪唑乙烟酸、双草醚及啶磺草胺具有不同程度的抗性,且乙酰乳酸合酶、过氧化物酶、过氧化氢酶和超氧化物歧化酶的活性随除草剂浓度的升高呈下降趋势。除了20×,30×的咪唑乙烟酸处理条件下过氧化氢酶和过氧化物酶的酶活性低于野生型HH31外,其他处理条件下ALS179的乙酰乳酸合酶、超氧化物歧化酶、过氧化氢酶和过氧化物酶的酶活性均高于野生型HH31。因此,本研究发现Ala179Val突变赋予了对ALS抑制剂类除草剂的广谱抗性,为后续ALS类除草剂广谱抗性水稻品系的培育提供遗传种质资源。 展开更多
关键词 水稻 乙酰乳酸合酶 alS抑制剂类除草剂 广谱抗性
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La元素对高导热Al-5Ni合金微观组织和性能的影响
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作者 李乘波 侯慧兵 +5 位作者 刘磊磊 余刚志 黄程毅 任月路 杜军 尹彩流 《广西大学学报(自然科学版)》 CAS 北大核心 2024年第4期826-834,共9页
Al-5Ni合金具有较高的导热性能,是新一代高导热材料的主要研究方向之一,但力学性能偏低,热-力矛盾显著。利用金相显微镜、扫描电镜、万能试验机、激光导热仪、数字电导率仪等,研究了微量稀土元素La添加对高导热Al-5Ni合金微观组织、力... Al-5Ni合金具有较高的导热性能,是新一代高导热材料的主要研究方向之一,但力学性能偏低,热-力矛盾显著。利用金相显微镜、扫描电镜、万能试验机、激光导热仪、数字电导率仪等,研究了微量稀土元素La添加对高导热Al-5Ni合金微观组织、力学性能及导热率和导电率的影响。结果表明,当La元素的添加量为0.2%(质量分数)时,合金α-Al晶粒细化程度最高,共晶组织内部纤维状的Al3Ni相近乎全部转化为球状,极限抗拉强度和硬度由未变质时的122.24 MPa和45.94 HV提升到140.48 MPa和47.28 HV,分别提升了14.92%和2.92%;合金的导热率和导电率几乎没有下降,为213.23 W/(m·K)和31.84 MS/m。稀土变质La元素的变质处理有效缓解了Al-5Ni合金的热-力矛盾,显著提高合金的综合性能。 展开更多
关键词 al-5Ni合金 la元素 微观组织 导热率 导电率 力学性能
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Al-Sr-La中间合金改性对A356铝合金组织和性能的影响
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作者 顾文秀 周细应 +3 位作者 彭以辉 黄超 刘延辉 左舜贵 《材料热处理学报》 CAS CSCD 北大核心 2024年第5期70-80,共11页
采用Al-Sr-La中间合金对A356铝合金进行改性处理,研究了Sr和La对A356铝合金微观结构和力学性能的协同变质机制。结果表明:添加0.5 mass%的Al-Sr-La中间合金对A356铝合金的改性效果最佳,此时A356铝合金具有优良的显微组织与力学性能,其α... 采用Al-Sr-La中间合金对A356铝合金进行改性处理,研究了Sr和La对A356铝合金微观结构和力学性能的协同变质机制。结果表明:添加0.5 mass%的Al-Sr-La中间合金对A356铝合金的改性效果最佳,此时A356铝合金具有优良的显微组织与力学性能,其α-Al相的晶粒细小,二次枝晶臂间距(SDAS)降低至14.2μm,较未改性的A356铝合金降低了36.6%,针状共晶Si转变为蠕虫状共晶Si,平均晶粒尺寸减小至0.86μm。与未改性的A356铝合金相比,添加0.5 mass%的Al-Sr-La中间合金改性后,合金的抗拉强度增加了22.4%,屈服强度增加了11.1%,伸长率增加了89.7%。最后,在实验结果的基础上,结合凝固理论,研究了Sr和La的协同变质机制。Sr吸附于Si相生长界面上,产生孪晶平面,抑制Si相的生长,使得Si以孪晶凹谷机制生长,实现对共晶Si的改性;La则由于Sr对Si的作用,使得La在共晶Si的凹槽处聚集,阻碍了Si的生长,改善共晶Si的形貌。 展开更多
关键词 al-Sr-la中间合金 显微组织 协同变质机制 力学性能
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高导压铸Al-La合金组织及性能研究
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作者 裘珂可 周其良 +4 位作者 郭潘狄 彭暄霖 胡波 李德江 曾小勤 《铸造》 CAS 2024年第7期947-954,共8页
研究了La含量(4%、6%、8%、10%)对压铸Al-La合金的微观组织、力学性能以及导电导热性能的影响。La在铝基体中的固溶度极小,易富集于α-Al凝固界面前沿而造成成分过冷,降低α-Al周围液相的结晶温度,进而抑制α-Al的生长而实现细化。凝固... 研究了La含量(4%、6%、8%、10%)对压铸Al-La合金的微观组织、力学性能以及导电导热性能的影响。La在铝基体中的固溶度极小,易富集于α-Al凝固界面前沿而造成成分过冷,降低α-Al周围液相的结晶温度,进而抑制α-Al的生长而实现细化。凝固过程中生成的Al11La3第二相不仅可以强化合金,还可作为α-Al的异质形核点以实现细化,这得益于其与α-Al基体5.96%的较小错配度。随着La含量从4%增加到10%,合金的屈服强度与抗拉强度分别从48.6MPa、113.9MPa提升到92.3MPa、186.7MPa,但伸长率从26.1%降低至9.6%。此外,Al-La合金的热导率、电导率随La含量的增加大致呈线性下降趋势,分别从207.8 W/(m·K)、32.0 MS/m下降至173.1 W/(m·K)、26.1 MS/m。 展开更多
关键词 al-la合金 第二相 力学性能 电导率 热导率
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Additively manufactured Ti–Ta–Cu alloys for the next-generation load-bearing implants 被引量:1
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作者 Amit Bandyopadhyay Indranath Mitra +4 位作者 Sushant Ciliveri Jose D Avila William Dernell Stuart B Goodman Susmita Bose 《International Journal of Extreme Manufacturing》 SCIE EI CAS CSCD 2024年第1期353-374,共22页
Bacterial colonization of orthopedic implants is one of the leading causes of failure and clinical complexities for load-bearing metallic implants. Topical or systemic administration of antibiotics may not offer the m... Bacterial colonization of orthopedic implants is one of the leading causes of failure and clinical complexities for load-bearing metallic implants. Topical or systemic administration of antibiotics may not offer the most efficient defense against colonization, especially in the case of secondary infection, leading to surgical removal of implants and in some cases even limbs. In this study, laser powder bed fusion was implemented to fabricate Ti3Al2V alloy by a 1:1 weight mixture of CpTi and Ti6Al4V powders. Ti-Tantalum(Ta)–Copper(Cu) alloys were further analyzed by the addition of Ta and Cu into the Ti3Al2V custom alloy. The biological,mechanical, and tribo-biocorrosion properties of Ti3Al2V alloy were evaluated. A 10 wt.% Ta(10Ta) and 3 wt.% Cu(3Cu) were added to the Ti3Al2V alloy to enhance biocompatibility and impart inherent bacterial resistance. Additively manufactured implants were investigated for resistance against Pseudomonas aeruginosa and Staphylococcus aureus strains of bacteria for up to 48 h. A 3 wt.% Cu addition to Ti3Al2V displayed improved antibacterial efficacy, i.e.78%–86% with respect to CpTi. Mechanical properties for Ti3Al2V–10Ta–3Cu alloy were evaluated, demonstrating excellent fatigue resistance, exceptional shear strength, and improved tribological and tribo-biocorrosion characteristics when compared to Ti6Al4V. In vivo studies using a rat distal femur model revealed improved early-stage osseointegration for alloys with10 wt.% Ta addition compared to CpTi and Ti6Al4V. The 3 wt.% Cu-added compositions displayed biocompatibility and no adverse infammatory response in vivo. Our results establish the Ti3Al2V–10Ta–3Cu alloy’s synergistic effect on improving both in vivo biocompatibility and microbial resistance for the next generation of load-bearing metallic implants. 展开更多
关键词 TI6al4V load-bearing implants additive manufacturing 3D printing antibacterial performance
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The regulation of ferrocene-based catalysts on heat transfer in highpressure combustion of ammonium perchlorate/hydroxyl-terminated polybutadiene/aluminum composite propellants 被引量:1
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作者 Jinchao Han Songqi Hu Linlin Liu 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第5期174-186,共13页
The regulation of the burning rate pressure exponent for the ammonium perchlorate/hydroxylterminated polybutadiene/aluminum(AP/HTPB/Al)composite propellants under high pressures is a crucial step for its application i... The regulation of the burning rate pressure exponent for the ammonium perchlorate/hydroxylterminated polybutadiene/aluminum(AP/HTPB/Al)composite propellants under high pressures is a crucial step for its application in high-pressure solid rocket motors.In this work,the combustion characteristics of AP/HTPB/Al composite propellants containing ferrocene-based catalysts were investigated,including the burning rate,thermal behavior,the local heat transfer,and temperature profile in the range of 7-28 MPa.The results showed that the exponent breaks were still observed in the propellants after the addition of positive catalysts(Ce-Fc-MOF),the burning rate inhibitor((Ferrocenylmethyl)trimethylammonium bromide,Fc Br)and the mixture of Fc Br/catocene(GFP).However,the characteristic pressure has increased,and the exponent decreased from 1.14 to 0.66,0.55,and 0.48 when the addition of Ce-FcMOF,Fc Br and Fc Br/GFP in the propellants.In addition,the temperature in the first decomposition stage was increased by 7.50℃ and 11.40℃ for the AP/Fc Br mixture and the AP/Fc Br/GFP mixture,respectively,compared to the pure AP.On the other hand,the temperature in the second decomposition stage decreased by 48.30℃ and 81.70℃ for AP/Fc Br and AP/Fc Br/GFP mixtures,respectively.It was also found that Fc Br might generate ammonia to cover the AP surface.In this case,a reaction between the methyl in Fc Br and perchloric acid caused more ammonia to appear at the AP surface,resulting in the suppression of ammonia desorption.In addition,the coarse AP particles on the quenched surface were of a concave shape relative to the binder matrix under low and high pressures when the catalysts were added.In the process,the decline at the AP/HTPB interface was only exhibited in the propellant with the addition of Ce-Fc-MOF.The ratio of the gas-phase temperature gradient of the propellants containing catalysts was reduced significantly below and above the characteristic pressure,rather than 3.6 times of the difference in the blank propellant.Overall,the obtained results demonstrated that the pressure exponent could be effectively regulated and controlled by adjusting the propellant local heat and mass transfer under high and low pressures. 展开更多
关键词 AP/HTPB/al propellants Heat transfer High-pressure combustion Ferrocene-based catalysts Pressure exponent
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稀土La、Ce和Y对Al-6.5Si-5.5Cu-0.2Zr-0.01Sr-0.06Ti-0.2RE合金组织和力学性能的影响
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作者 刘乐乐 孙智伟 +1 位作者 许晓静 洪志恒 《热加工工艺》 北大核心 2024年第19期132-137,共6页
通过SEM、OM、EDS、拉伸试验,研究了稀土La、Ce和Y对Al-6.5Si-5.5Cu-0.2Zr-0.01Sr-0.06Ti-0.2RE铸态合金组织以及力学性能的影响。结果表明:稀土元素Ce和Y明显改善了合金的微观组织,细化了α-Al相,并且提高了共晶Si相的变质效果,而La元... 通过SEM、OM、EDS、拉伸试验,研究了稀土La、Ce和Y对Al-6.5Si-5.5Cu-0.2Zr-0.01Sr-0.06Ti-0.2RE铸态合金组织以及力学性能的影响。结果表明:稀土元素Ce和Y明显改善了合金的微观组织,细化了α-Al相,并且提高了共晶Si相的变质效果,而La元素对合金的改善效果较差。加入稀土元素Ce和Y的铸态合金具有较高的力学性能,硬度分别为76.8 HV和79.05 HV,抗拉强度分别为182.61 MPa和216.83 MPa,断后伸长率分别为6.03%和7.84%。而具有La元素的铸态合金的力学性能较低,硬度为73.58 HV,抗拉强度为160.58 MPa,断后伸长率为3.21%。具有稀土元素La的铸态合金的抗晶间腐蚀性能较好,腐蚀坑较小,最大腐蚀深度达90μm,腐蚀等级为三级。而具有稀土元素Ce和Y的铸态合金的抗晶间腐蚀性逐渐变差,最大腐蚀深度分别为110.21μm和145.68μm。 展开更多
关键词 al-SI-CU合金 稀土 微观组织 力学性能
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La/Al天然沸石对水中F^(-)的吸附及再生
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作者 钱程 张峰榛 +1 位作者 曾奇 龚长林 《化工新型材料》 CAS CSCD 北大核心 2024年第1期214-219,共6页
以天然沸石为原料,制备La/Al负载天然沸石,用于水中F^(-)的吸附,并对其吸附动力学、等温吸附性能、再生能力和吸附机理进行探讨。结果表明,该吸附剂对F^(-)的吸附符合拟二级动力学模型和Langmuir模型,在298K温度条件下,理论最大吸附量为... 以天然沸石为原料,制备La/Al负载天然沸石,用于水中F^(-)的吸附,并对其吸附动力学、等温吸附性能、再生能力和吸附机理进行探讨。结果表明,该吸附剂对F^(-)的吸附符合拟二级动力学模型和Langmuir模型,在298K温度条件下,理论最大吸附量为19.2mg/g。pH的升高不利于F^(-)的吸附。Cl^(-)、NO_(3)^(-)对F^(-)的吸附影响较小,而HCO_(3)^(-)和H_(2)PO_(4)^(-)的存在不利于F^(-)的吸附。在0.5mol/L NaOH条件下,经过5次循环再生,吸附剂对F^(-)的吸附量降低16.7%。SEM、BET、EDS-mapping和XPS分析表明,F^(-)的吸附机理主要为配体交换。 展开更多
关键词 la/al 天然沸石 F^(-)吸附 再生
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稀土La对铸造Al-Si合金组织与性能的影响
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作者 谷立东 王乐耘 +2 位作者 应韬 杨剑英 李德江 《铸造技术》 CAS 2024年第5期475-478,共4页
研究了不同含量的稀土La对铸造铝硅二元合金的显微组织与性能的影响。结果表明,少量La的加入可使共晶硅组织聚集情况改善,对基体割裂减弱,当La含量为0.15%(质量分数)时,可使铝基体具有细化的近非枝晶组织,同时微观上共晶硅的尺寸显著减... 研究了不同含量的稀土La对铸造铝硅二元合金的显微组织与性能的影响。结果表明,少量La的加入可使共晶硅组织聚集情况改善,对基体割裂减弱,当La含量为0.15%(质量分数)时,可使铝基体具有细化的近非枝晶组织,同时微观上共晶硅的尺寸显著减小。随着La含量的增加,铝硅合金的屈服强度与伸长率呈现先增加后稳定的趋势,电导率递增。共晶硅的细化有利于降低Si对电子散射的阻挡,从而使合金电导率提升。综合来看,当选用0.15%的La加入时,铸造铝硅合金具有综合最优的显微组织、力学性能和导电性能。 展开更多
关键词 铝硅合金 稀土 共晶硅 力学性能
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Crack elimination and strength enhancement mechanisms of selective laser melted Si-modified Al−Mn−Mg−Er−Zr alloy
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作者 Jiang YU Yao-xiang GENG +2 位作者 Hong-bo JU Zhi-jie ZHANG Jun-hua XU 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2024年第8期2431-2441,共11页
In order to increase the processability and process window of the selective laser melting(SLM)-fabricated Al−Mn−Mg−Er−Zr alloy,a novel Si-modified Al−Mn−Mg−Er−Zr alloy was designed.The effect of Si alloying on the sur... In order to increase the processability and process window of the selective laser melting(SLM)-fabricated Al−Mn−Mg−Er−Zr alloy,a novel Si-modified Al−Mn−Mg−Er−Zr alloy was designed.The effect of Si alloying on the surface quality,processability,microstructure,and mechanical properties of the SLM-fabricated alloy was studied.The results showed that introducing Si into the Al−Mn−Mg−Er−Zr alloy prevented balling and keyhole formation,refined the grain size,and reduced the solidification temperature,which eliminated cracks and increased the processability and process window of the alloy.The maximum relative density of the SLM-fabricated Si/Al−Mn−Mg−Er−Zr alloy reached 99.6%.The yield strength and ultimate tensile strength of the alloy were(371±7)MPa and(518±6)MPa,respectively.These values were higher than those of the SLM-fabricated Al−Mn−Mg−Er−Zr and other Sc-free Al−Mg-based alloys. 展开更多
关键词 selective laser melting al−Mn−Mg−Er−Zr−Si alloy surface roughness PROCESSABILITY mechanical properties
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From mice to humans:a need for comparable results in mammalian neuroplasticity
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作者 Marco Ghibaudi Enrica Boda Luca Bonfanti 《Neural Regeneration Research》 SCIE CAS 2025年第2期464-466,共3页
Brain plasticity-A universal tool with many variations:The study of brain plasticity has been gaining interest since almost a century and has now reached a huge amount of information(>80,000 results in PubMed).Over... Brain plasticity-A universal tool with many variations:The study of brain plasticity has been gaining interest since almost a century and has now reached a huge amount of information(>80,000 results in PubMed).Overall,different types of plasticity,including stem cell-driven genesis of new neurons(adult neurogenesis),cells in arrested maturation(dormant neurons),neuro-glial and synaptic plasticity,can coexist and contribute to grant plastic changes in the brain,from a cellular to system level(Benedetti and Couillard-Despres,2022;Bonfanti et al.,2023). 展开更多
关键词 PlaSTICITY al. ARREST
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HZSM-5 zeolites undergoing the high-temperature process for boosting the bimolecular reaction in n-heptane catalytic cracking
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作者 Chenggong Song Zhenzhou Ma +6 位作者 Xu Hou Hao Zhou Huimin Qiao Changchang Tian Li Yin Baitang Jin Enxian Yuan 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第2期136-144,共9页
High-temperature treatment is key to the preparation of zeolite catalysts.Herein,the effects of hightemperature treatment on the property and performance of HZSM-5 zeolites were studied in this work.X-Ray diffraction,... High-temperature treatment is key to the preparation of zeolite catalysts.Herein,the effects of hightemperature treatment on the property and performance of HZSM-5 zeolites were studied in this work.X-Ray diffraction,N2physisorption,27Al magic angle spinning nuclear magnetic resonance(MAS NMR),and temperature-programmed desorption of ammonia results indicated that the hightemperature treatment at 650℃ hardly affected the inherent crystal and texture of HZSM-5zeolites but facilitated the conversion of framework Al to extra-framework Al,reducing the acid site and enhancing the acid strength.Moreover,the high-temperature treatment improved the performance of HZSM-5 zeolites in n-heptane catalytic cracking,promoting the conversion and light olefins yield while inhibiting coke formation.Based on the kinetic and mechanism analysis,the improvement of HZSM-5 performance caused by high-temperature treatment has been attributed to the formation of extra-framework Al,which enhanced the acid strength,facilitated the bimolecular reaction,and promoted the entropy change to overcome a higher energy barrier in n-heptane catalytic cracking. 展开更多
关键词 HZSM-5 N-HEPTANE Catalytic cracking High-temperature treatment Extra-framework al
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Pit density reduction for AlN epilayers grown by molecular beam epitaxy using Al modulation method
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作者 Huan Liu Peng-Fei Shao +8 位作者 Song-Lin Chen Tao Tao Yu Yan Zi-Li Xie Bin Liu Dun-Jun Chen Hai Lu Rong Zhang Ke Wang 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第10期95-101,共7页
We have investigated homoepitaxy of AlN films grown by molecular beam epitaxy on AlN/sapphire templates byadopting both the continuous growth method and the Al modulation epitaxy(AME)growth method.The continuous growt... We have investigated homoepitaxy of AlN films grown by molecular beam epitaxy on AlN/sapphire templates byadopting both the continuous growth method and the Al modulation epitaxy(AME)growth method.The continuous growthmethod encounters significant challenges in controlling the growth mode.As the precise Al/N=1.0 ratio is difficult toachieve,either the excessive Al-rich or N-rich growth mode occurs.In contrast,by adopting the AME growth method,sucha difficulty has been effectively overcome.By manipulating the supply time of the Al and nitrogen sources,we were able toproduce AlN films with much improved surface morphology.The first step of the AME method,only supplying Al atoms,is important to wet the surface and the Al adatoms can act as a surfactant.Optimization of the initial Al supply time caneffectively reduce the pit density on the grown AlN surface.The pits density dropped from 12 pits/μm^(2)to 1 pit/μm^(2)andthe surface roughness reduced from 0.72 nm to 0.3 nm in a 2×2μm^(2)area for the AME AlN film homoepitaxially grownon an AlN template. 展开更多
关键词 al modulation epitaxy molecular beam epitaxy alN PITS
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Damping properties and mechanism of aluminum matrix composites reinforced with glass cenospheres
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作者 Kai SUN Lin WANG +5 位作者 Hang SU Jia-yi GENG Qiang ZHANG Bo MENG Zeng-yan WEI Gao-hui WU 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2024年第9期2743-2755,共13页
The damping properties were improved by preparing Al matrix composites reinforced with glass cenospheres through the pressure infiltration method.Transmission electron microscopy and scanning electron microscopy were ... The damping properties were improved by preparing Al matrix composites reinforced with glass cenospheres through the pressure infiltration method.Transmission electron microscopy and scanning electron microscopy were employed to characterize the microstructure of the composites.The low-frequency damping properties were examined by using a dynamic mechanical thermal analyzer,aiming at exploring the changing trend of damping capacity with strain,temperature,and frequency.The findings demonstrated that the damping value rose as temperature and strain increased,with a maximum value of 0.15.Additionally,the damping value decreased when the frequency increased.Dislocation damping under strain and interfacial damping under temperature served as the two primary damping mechanisms.The increase in the density of dislocation strong pinning points following heat treatment reduced the damping value,which was attributed to the heat treatment enhancement of the interfacial bonding force of the composites. 展开更多
关键词 glass cenospheres al matrix composites MICROSTRUCTURE low-frequency damping properties
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Microstructure Regulation and Combustion Performance Optimization of PVDF/Al Composite Powder by Non-covalent Functionalized Graphenes
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作者 易卓然 DENG Haoyuan +2 位作者 QIN Mei 孙一 LUO Guoqiang 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第4期904-911,共8页
Graphene prepared by non-covalent modification of sulfonated poly(ether-ether-ketone)(SPG)was combined with polyvinylidene fluoride(PVDF)/Al to improve the PVDF/Al thermal conductivity while reducing the effect of the... Graphene prepared by non-covalent modification of sulfonated poly(ether-ether-ketone)(SPG)was combined with polyvinylidene fluoride(PVDF)/Al to improve the PVDF/Al thermal conductivity while reducing the effect of the thermal resistance at the graphene-polymer interface.The regulation rule of SPG with different contents on the energy release of fluorine-containing system was studied.When the content of SPG is 4%,the peak pressure and rise rate of SPG/PVDF/Al composite powder during ignition reach the maximum of 4845.28 kPa and 8683.58 kPa/s.When the content of SPG is 5%,the PVDF/Al composite powder is completely coated by SPG,and the calorific value of the material reachs the maximum of 29.094 kJ/g.Through the design and micro-control of the composite powder,the calorific value of the material can be effectively improved,but the improvement of the mass release rate still depends on the graphene content and surface modification state. 展开更多
关键词 energetic materials PVDF/al composites graphene modification energy release combustion
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Mechanical properties and interfacial characteristics of 6061 Al alloy plates fabricated by hot-roll bonding
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作者 Zongan Luo Xin Zhang +3 位作者 Zhaosong Liu Hongyu Zhou Mingkun Wang Guangming Xie 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第8期1890-1899,共10页
This work aims to investigate the mechanical properties and interfacial characteristics of 6061 Al alloy plates fabricated by hotroll bonding(HRB)based on friction stir welding.The results showed that ultimate tensile... This work aims to investigate the mechanical properties and interfacial characteristics of 6061 Al alloy plates fabricated by hotroll bonding(HRB)based on friction stir welding.The results showed that ultimate tensile strength and total elongation of the hot-rolled and aged joints increased with the packaging vacuum,and the tensile specimens fractured at the matrix after exceeding 1 Pa.Non-equilibrium grain boundaries were formed at the hot-rolled interface,and a large amount of Mg_(2)Si particles were linearly precipitated along the interfacial grain boundaries(IGBs).During subsequent heat treatment,Mg_(2)Si particles dissolved back into the matrix,and Al_(2)O_(3) film remaining at the interface eventually evolved into MgO.In addition,the local IGBs underwent staged elimination during HRB,which facilitated the interface healing due to the fusion of grains at the interface.This process was achieved by the dissociation,emission,and annihilation of dislocations on the IGBs. 展开更多
关键词 6061 al alloy hot-roll bonding VACUUM mechanical properties interfacial grain boundaries
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Microstructure,Corrosion and Mechanical Properties of Medium-Thick 6061-T6 Alloy/T2 Pure Cu Dissimilar Joints Produced by Double Side Friction Stir Z Shape Lap-Butt Welding
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作者 Jiuxing Tang Guoxin Dai +5 位作者 Lei Shi Chuansong Wu Sergey Mironov Surendra Kumar Patel Song Gao Mingxiao Wu 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2024年第2期385-400,共16页
A novel double side friction stir Z shape lap-butt welding(DS-FSZW)process was proposed to achieve excellent mechanical properties of Al/Cu medium-thick dissimilar joints.The influence of welding parameters on weld mi... A novel double side friction stir Z shape lap-butt welding(DS-FSZW)process was proposed to achieve excellent mechanical properties of Al/Cu medium-thick dissimilar joints.The influence of welding parameters on weld microstructure and properties of DS-FSZW joint were systematically investigated.It indicated that defect-free medium-thick Al/Cu DS-FSZW joint could be achieved under an optimal welding parameter.DS-FSZW joint was prone to form void defects in the bottom of the second-pass weld.The recrystallization mechanisms at the top and middle of the weld nugget zone(WNZ)were continuous dynamic recrystallization(CDRX)and geometric dynamic recrystallization(GDRX).While the major recrystallization mechanism at the bottom of the WNZ was GDRX.DS-FSZW joint of the optimal welding condition with 850 r/min-400 mm/min was produced with a continuous thin and crack-free IMCs layer at the Al/Cu interface,and the maximum tensile strength of this joint is 160.57 MPa,which is equivalent to 65.54%of pure Cu base material.Moreover,the corrosion resistance of Al/Cu DS-FSZW joints also achieved its maximum value at the optimal welding parameter of 850 r/min-400 mm/min.It demonstrates that the DS-FSZW process can simultaneously produce medium-thick Al/Cu joints with excellent mechanical performance and corrosion resistance. 展开更多
关键词 DS-FSZW al/Cu dissimilar joint Corrosion behaviour Intermetallic compounds MICROSTRUCTURE Mechanical properties
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