共查询到19条相似文献,搜索用时 468 毫秒
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通过先对Zr55Ni5Al10Cu30合金熔体施加脉冲电流处理,再利用非真空吸铸法制备出Zr55Ni5Al10Cu30块体非晶合金的方式,研究了电脉冲孕育处理对非晶热稳定性及退火晶化的影响。差分扫描量热(DSC)及X射线衍射(XRD)分析结果表明:经电脉冲孕育处理后Zr55Ni5Al10Cu30块体非晶合金的玻璃转变温度上升,晶化温度降低,过冷液相区变窄,同时玻璃转变激活能和晶化激活能有所减少。电脉冲孕育处理没有改变Zr55Ni5Al10Cu30块体非晶合金退火晶化相演变过程,但提高了非晶退火晶化率。电脉冲孕育处理对Zr55Ni5Al10Cu30块体非晶合金的晶化起到了促进作用。 相似文献
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为了改善Al-Cu合金的热裂倾向,以Al-5.65%Cu合金为研究对象,采用超声波熔体处理技术,研究了超声波对Al-5.65%Cu合金热裂倾向性的影响。利用光学显微镜、热裂测定仪、扫描电镜等分析测试手段,分析了Al-5.65%Cu合金的宏观组织、微观组织、热裂性能及断口形貌等。研究结果表明:Al-5.65%Cu熔体经超声波处理后,合金的结晶组织得到细化,合金的抗裂力值增大,热裂倾向明显降低;在较高温度下处理熔体,获得的Al-5.65%Cu合金抗裂力值也较大;经超声波处理后,热裂断口为沿晶断裂并且存在明显的液膜拉伸痕迹;经超声波处理后的熔体,其冷却速度比没有超声处理的合金要缓慢。 相似文献
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合金元素对铸造Al-4.5Cu合金准固态力学行为的影响 总被引:3,自引:0,他引:3
研究了铸造Al-4.5Cu合金的准固态力学行为及几种合金元素对其凝固行为的影响。结果表明:Si,Ce,La,Ti及Zr元素可有效减小Al-4.5Cu合金的结晶范围,从而使其热裂倾向性降低;La元素的加入可提高Al-4.5Cu合金的热裂抗力:并研制了一种新型Al-4.5Cu合金,该合金具有良好的室温与高温综合性能。 相似文献
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在铸造Al-7Zn-2.5Mg-Cu合金中分别加入0.2%、0.5%、0.8%和1.2%的Al-5Ti-B细化剂,研究了细化剂加入量对合金的微观组织、抗拉强度和热裂倾向的影响.结果表明,Al-5Ti-B细化剂明显细化Al-7Zn-2.5Mg-Cu合金的组织.随着细化剂添加量的增加,晶粒尺寸先减小,后稍微增大,在加入量为0.8%时,晶粒尺寸最小,为66μm.随着晶粒尺寸的减小,Al-7Zn-2.5Mg-Cu合金的共晶体数量增多,抗拉强度增加,热裂倾向减小.抗拉强度与晶粒尺寸的关系为σb=47.227 11+1 325.354 77×d-1/2,热裂倾向与晶粒尺寸的关系为H=41.739 12+0.573 3×d.共晶组织也影响合金的抗拉强度和热裂倾向.试验范围内,共晶组织增多,抗拉强度降低,热裂倾向先降低后升高. 相似文献
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合金元素对Al—Cu合金热裂倾向的影响 总被引:13,自引:3,他引:13
为寻求一种低热裂倾向的高强韧造铝合金材料,研究了Cu,Zr和V3种元素对Al-Cu合金热裂倾向的影响,结果表明,V明显降低材料的热裂倾向;Zr含量低时轻微增大合金的热裂倾向,含量高时强烈增大热裂倾向,在4.5%-5.5%范围内Cu增大热裂倾向,Zr和V对合金热裂倾向的不同影响在于V主要存在于晶内,而Zr则部分存在于晶界。 相似文献
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采用单螺旋法和铸造性能多功能测试仪测定了铸造Al-7Si-xCu-0.3Mg(x=1.5%~3.5%,质量分数)合金的流动性、线收缩率和热裂倾向.结合Pandat相平衡软件计算相图、θ相(Al2Cu)的晶体结构特点和凝固显微组织的扫描电镜与能谱分析仪(SEM-EDX)分析,讨论了Cu含量对试验合金的流动性、线收缩率和热裂倾向的影响.随着Cu含量的同时,合金凝固时低熔点富Cu的共晶θ相(Al2Cu)明显增多,容易形成α(Al)枝晶骨架网,导致合金的流动性降低,线收缩率增加,热裂倾向增大. 相似文献
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《中国有色金属学会会刊》2020,30(2):318-332
The hot cracking tendency of 7075 semi-solid alloy under different conditions was studied by critical diameter method. The experiment and simulation results show that the dendrite arms of the rod grow from the edge to the center. The smaller the diameter of the rod is, the more obvious the directional growth of dendrite is, and the greater the tendency of hot cracking is. Compared with ordinary melt, for semi-solid slurry, increasing mould temperature or decreasing pouring temperature can significantly decrease hot cracking tendency of 7075 alloy, decreasing hot cracking grade from 256 to 100 mm2. Furthermore, based on the RDG criterion, the effects of solidification conditions on the hot cracking tendency were discussed combined with simulation. At the same time, the application and development of RDG criterion were also researched. 相似文献
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脉冲电场对KS282合金凝固组织的影响 总被引:1,自引:1,他引:1
以KS282合金凝固组织中的初生硅相作为对象,研究了脉冲电场孕育处理对KS282合金初生相形态的影响,分析了扫描电子显微镜(SEM)下组织形态的变化、断口金相,以及DSC曲线中凝固点位置的改变。结果发现,电脉冲孕育处理对多元高硅铝合金有变质作用,增加了合金凝固过程的热力学过冷度,提高了初生硅相形核率。 相似文献
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The metallographic structure of LM-29 aluminum-silicon alloy modified by electric pulse treatment has been investigated and compared with those untreated. The solidification structure of LM-29 alloy has been analyzed by means of M1AP3 Quantimet image processing and analysis system, and then the solidification process has been analyzed by means of differential scanning calorimetry (DSC). The results indicate that the primary silicon phase was refined remarkably by electric pulse while the tensile strength and elongation properties increased accordingly. Electric pulse treatment can also increase the binding power between silicon clusters and alloy melt matrix, as a result, the precipitation of primary silicon phase is suppressed to meet the demand of supercooling degree for nucleating, correspondingly. The electric pulse modification has great influence on the size of silicon atomic cluster as well as its distribution in the melt, subsequently, leads to the refinement of solidification structure. 相似文献
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Effects of the melt pulse electric current and thermal treatment on solidification structures of A356 alloy were investigated.In the experiments.the low temperature melt(953K and 903K)treated by pulse electric current was mixed with high temperature metl(1223K).By the control experiments,the results show that the solidification structure of A356 alloy is refined apparently by the pulse electric current together with melt thermal treatment process,and the mechanical properties.especially the elongation ratio of the specimen treated is improved greatly.The structure change of the melt by pulse electric current and melt thermal treatment is the main reason for the refinement of the solidification structure of A356 alloy. 相似文献
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在HRS定向凝固设备上进行了合金热裂试验,采用半定量方法评定了定向凝固Al-Cu和Renel25合金热裂倾向。观察了合金的晶界,并分析讨论了其对合金热裂的影响。用晶界状态分析的结果与试验结果完全一致。证明了晶界状态对热裂纹的形成有重要影响,其影响包括对晶间结合力的破坏作用和对晶界凝固收缩的补偿作用。晶界状态对热裂影响的综合作用取决于晶界低熔点相的分布和数量。 相似文献
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H. J. Wang J. Xu Y. L. Kang M. O. Tang Z. F. Zhang 《Journal of Materials Engineering and Performance》2014,23(4):1165-1172
High crack tendency is easy to occur during preparation of the castings and ingots of Al-Zn-Mg-Cu alloy, and it is most difficult to be solved due to the characteristics for the series alloy. As-cast microstructures and hot cracking tendency of Al-Zn-Mg-Cu alloy with different addition levels of Al-5Ti-1B-1Re were investigated in the paper. Moreover, solidification characteristics of the experimental alloys with different mass fractions of Al-5Ti-1B-1Re were analyzed, and the addition content of Al-5Ti-1B-1Re was optimized. These results indicate that the microstructure of the experimental alloys with Al-5Ti-1B-1Re refiner is fine obviously, the dendrite shape refined by Al-5Ti-1B-1Re becomes more globular, the grain boundary is smoother, and the SDAS is smaller compared with the alloy without Al-5Ti-1B-1Re. When the addition level of the grain refiner is less than 0.2%, the hot cracking tendency for the experimental alloy is reduced. The addition of 0.2% Al-5Ti-1B-1Re is best effective to improve the as-cast microstructures and hot cracking of Al-Zn-Mg-Cu alloy, and the best addition level of Al-5Ti-1B-1Re refiner is 0.2%. 相似文献