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共晶高熵合金是凝固过程中发生共晶转变的多组元合金,具有优异的液态充型能力和机械性能,适用于生产形状复杂、对力学性能要求较高且不能进行热机械处理的零件。共晶高熵合金具有4种及以上元素,且相组成和组织形貌对合金成分变化不敏感,因此具有很大的性能调控空间及工艺窗口。通过调控共晶高熵合金的相组成及组织形貌可使其叠加各种优异性能。本文从设计方法、制备工艺、组织结构、力学及理化性能等方面综述了共晶高熵合金的研究现状,并对共晶高熵合金未来的发展进行展望。 相似文献
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共晶高熵合金由于优异的铸造性能以及优良的强塑性匹配受到了广泛关注,然而,共晶高熵合金的成分设计始终是一项挑战。针对这一项挑战,国内外学者开发了多种共晶高熵合金的成分设计方法。每种方法各有特点和局限性,本文对共晶高熵合金的成分设计方法进行了全面评述。 相似文献
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近十几年来,作为一种研究热门的新型合金,高熵合金已获得了材料界广泛的关注.其中,以等原子比CoCrFeNiMn合金为原型,已报道大量力学性能优异的fcc结构的高熵合金.近几年,由于其优异的铸造成形性能与综合力学性能,共晶高熵合金也逐渐得到科研人员的重视.本工作选取CoCrFeNiNbx合金体系,以析出强化型高熵合金和共... 相似文献
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激光熔覆技术具有高的冷却速度、低的稀释率、涂层与基体冶金结合等优点,采用激光熔覆技术制备耐磨性和耐腐蚀好的高熵合金涂层是近几年高熵合金领域的研究热点之一。首先概括了激光熔覆技术制备的高熵合金体系及组织结构特征,大多高熵合金涂层以固溶相为主,少数合金涂层形成了非晶相,与熔炼制备高熵合金块体材料相比,涂层组织具有均匀、细小致密等特点。然后介绍了涂层的性能特征,涂层具有较高的硬度、良好的耐磨性,同时指明高耐磨性涂层不仅具有高的硬度,同时还需要具有一定的塑韧性。涂层合金中大多包含有Al、Cr、Si和Co等形成稳定氧化膜的元素,呈现优异的抗腐蚀性能。随后重点概述了合金元素(Al、Mo、V、Ti、B、Ni、Nb和Cu等)、熔覆工艺参数(激光功率、扫描速度和预制层粉末厚度)和热处理工艺对涂层组织结构和性能的影响规律。其中,熔覆工艺参数对涂层组织结构和性能的影响研究相对较少,将是未来研究的重点内容之一。最后对激光熔覆技术制备高熵合金涂层存在的问题和未来的研究方向做了展望。 相似文献
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利用激光熔覆技术在Q235基体表面制备CoCrFeNiTi0.8Nb
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Fe相及其形貌对共晶Al-Si合金性能的影响 总被引:1,自引:0,他引:1
应用光学显微镜、万能拉伸实验机及XRD等,研究了不同Fe含量及其Fe相形貌对共晶Al-Si合金(ADC12)组织性能的影响,并利用扫描电镜(SEM)及能谱分析了Fe相的含量、形貌及铸件中Fe等元素的面分布。试验发现,随着Fe含量的上升,铸件的抗拉强度及伸长率逐渐下降;当Fe的质量分数在1·0%左右时,其抗拉强度急剧下降,伸长率也下降很多。在Fe含量高的Al-Si合金中按一定的w(Mn)/w(Fe)比加入Mn,使铁相形貌由针状向块状和“田”字状转变,铸件的抗拉强度提高180%。 相似文献
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Jiafen Song Zishu Chai Jian Zheng Qingfeng Wu Feng He Zenan Yang Junjie Li Jincheng Wang Haiou Yang Zhijun Wang 《金属学报(英文版)》2021,34(8):1103-1108
High-entropy alloys have attracted broad research interests due to their unique and intriguing mechanical properties. As a category of high-entropy alloys, eutectic high-entropy alloys combine the advantages of eutectic and high-entropy alloys, with excellent mechanical properties and casting properties. Some eutectic high-entropy alloys have been developed and shown exciting properties. In this paper, based on the physical metallurgy of eutectic high-entropy alloy, medium-entropy alloy Fe_2NiCrNb_x was designed. The as-cast alloy is composed of FCC and Laves phases, Nb element promotes the formation of primary Laves phase, and the hardness of the alloy increases with the increase in Nb element. Among the four alloys, the eutectic chemical composition at eutectic point is Fe_2NiCrNb_(0.34); the alloy has a good strength and plastic balance. The ultimate comprehensive strength is 2267 MPa, and the fracture strain is 30.8%. The experiment data and analyses identified the eutectic points and the excellent mechanical behavior. Moreover, the expensive Co element was replaced by Fe element. This cheap medium-entropy alloy has promising prospect in the consideration of the cost performance ratio. 相似文献
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Huan Li Shuai Zeng Yong-Kang Zhou Hai-Long Li Hong-Wei Zhang Hai-Feng Zhang Zheng-Wang Zhu 《金属学报(英文版)》2022,35(10):1583
Superelasticity has been widely used in various fields. High elastic limit simultaneously with large superelasticity is urgent in the critical applications. In this study, we have employed the high entropy alloy (HEA) concept to develop a new TiHfNiFe-Nb eutectic HEA (EHEA) based on the TiNi-Nb eutectic alloy. The results show the directional catkin-like microstructure with the fiber eutectic in the center and the lamella eutectic in the outside form along the directional solidification direction when the growth rate is 60 mm/h. The corresponding specimens display the high strength of 1409 MPa and superelasticity of 3.1% in tension at room temperature, which is attributed to the synergetic effect of high entropy, preferred orientation, ordered body-centered cubic (B2) phase and disordered body-centered cubic phase in the eutectic structure. This work sheds light on designing the high-performance superelastic function materials with EHEAs. 相似文献
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In the present study,a series of AlCoCrxFeNi2.1 (x=0,0.25,0.5,0.75,1.0) eutectic high entropy alloys (EHEAs) have been designed and prepared.And the effect of Cr content on the microstructures and mechanical properties of the AlCoCrxFeNi2.1 alloys was systematically investigated.The results indicate that the AlCoCrxFeNi2.1 (x > 0) alloys exhibit almost complete lamellar eutectic microstructures with a mixture structure of FCC and B2 phases.And the AlCoFeNi2.1 alloy without Cr element exhibited a hypoeutectic microstructure with a primary B2 phase.In addition,the eutectic microstructures for AlCoCrxFeNi2.1 eutectic alloys do not change significantly.The room temperature compressive tests results show that with an increase in Cr content (from x =0 to x =1.0),the yield strength will first decrease,and thereafter increase.The trend is the opposite with the fracture strength and plastic strain.They show an increase trend at first,and then decrease.The AlCoCr0.5FeNi2.1 (Cr0.5) alloy shows the best comprehensive mechanical properties.The tensile yield strength,fracture strength,and elongation are 536.5 MPa,1062 MPa,and 13.8%,respectively.Furthermore,the Cr0.5 alloy also displays a high strength with a yield strength of 362 MPa at 700 ℃.In summary,by changing the Cr content,AlCoCrxFeNi2.1 eutectic high entropy alloys with excellent comprehensive mechanical properties were obtained and prepared. 相似文献
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将Al和Ti粉末按照摩尔比为3∶1预涂在AA6063铝合金表面进行激光熔覆处理。试验结果表明,采用合适的激光功率和扫描速度可获得无裂纹、无孔洞且表面平整的涂层。涂层由枝晶状Al3Ti和枝晶间纯Al组成,Al3Ti枝晶靠近试样表面一侧细小、而靠近基材一侧粗大,涂层和基材之间形成了良好的冶金结合。涂层的硬度(HV)可达500,显著改善了铝合金的表面性能。 相似文献
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共晶和过共晶铝硅合金活塞尺寸稳定性的研究 总被引:4,自引:0,他引:4
研究了两种共晶和两种过共晶铝硅合金活塞在200℃的长期时效过程中的尺寸稳定性。研究发现,随着时效时间的延长,所有活塞顶部的直径都呈现不可逆长大;过共晶铝合金活塞的尺寸稳定性高于共晶铝合金活塞;共晶铝硅合金活塞顶部直径有两次突然长大,而过共晶铝合金活塞仅有一次。作者初步解释了上述现象 相似文献
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综述了高熵合金(HEA)/碳化钨(WC)复合材料研究进展,主要介绍了以WC为基体的WC-HEA硬质合金和以HEA为基体的HEA/WC复合涂层,探究了高熵合金复合碳化钨材料强度、硬度、耐磨性、耐腐蚀性能提高的方式,并展望了高熵合金与WC相复合的发展前景与研究开发的重点。 相似文献
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采用真空电弧熔炼工艺制备了FeMoCrVTiSix(x=0、0.3、0.5、1)高熵合金,利用X射线衍射仪、扫描电镜、显微硬度计、万能试验机等设备研究了合金的组织和力学性能。结果表明,x=0时,合金由单一BCC固溶结构组成,随着Si含量增加,合金中逐渐析出(MoCrV)3Si相和(FeCrVSi)2(MoTi)的Laves相,x=1时,Laves相成为主相。随着Si含量增加,合金脆性随之增加,硬度(HV)也呈上升趋势,在x=1时达到最大值1113。 相似文献