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采用5种焊丝对2219铝铜合金进行MIG焊,研究了孕育剂Ti和Zr元素对焊缝组织和性能的影响.结果表明,Ti和Zr元素的细化作用是相容的,当焊丝中单独添加孕育剂Ti或Zr元素时,焊缝几乎由粗大的柱状晶组成.焊丝中复合添加少量的孕育剂Ti和Zr元素时,Ti和zr元素在熔池中分别形成Al3Ti和Al3Zr,促进了α(Al)非均质形核.随着焊丝中Ti和Zr元素含量的增加,焊缝组织逐步细化.当焊丝中Ti和Zr元素含量较高时,Ti和Zr元素还在熔池中形成大量的Al3(Ti,Zr)质点,促进α(Al)非均质形核,焊缝组织由细小均匀的等轴晶组成,显著提高了接头强度和塑性. 相似文献
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在ER2319焊丝的基础上,分别添加少量Ce、Cr及Mn元素制备了3种焊丝。采用光学显微镜、扫描电镜和能谱分析技术研究微量元素Ce、Cr和Mn对MIG焊缝组织和性能的影响。结果表明:Ce能够细化二次枝晶间距,但Ce易与Ti、Zr相互反应在晶界生成块状硬而脆的AlCuCeTiZrV复杂金属间化合物,降低了Ti和Zr的异质形核作用,使焊缝组织成柱态。而Cr和Mn则能促进A13Ti、Al3Zr以及复合析出物Al3(Zr,Ti)的析出,增加这些颗粒在高温条件下的稳定性,能够显著细化焊缝晶粒和晶界共晶相,提升接头的力学性能。但Mn的含量达到0.58%时,焊缝中心容易形成粗大树枝晶。 相似文献
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微量Cr、Mn、Ti、Zr细化7A55铝合金铸锭组织的效果与机理 总被引:6,自引:7,他引:6
采用光学显微镜、扫描电镜及能谱分析术研究了复合添加微量Cr、Mn、Ti、Zr细化7A55合金铸锭组织的效果和机理.结果表明:复合添加0.04%Ti 0.17%Zr能在一定程度上细化7A55合金铸锭组织,复合添加0.20%Cr 0.20%Mn 0.03%Ti能够显著细化铸锭组织,其细化机理为含有Cr、Mn的原子团簇作为Al3Ti形核的基底促使α-Al成核;复合添加微量0.04%Cr 0.04%Mn 0.03%Ti 0.18%Zr产生了极强烈的晶粒细化效果,其细化机理为含有Cr、Mn的原子团簇作为Al3Ti、Al3Zr共同形核的基底使Al3(TixZr1-x)形核,Al3(TixZr1-x)使α-Al形核.随着Cr、Mn含量增加,铸锭晶粒向枝晶化、粗大化方向发展. 相似文献
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采用Al—Mg及Al-Si两种焊丝分别对SiCp/LD2复合材料进行了MIG焊,利用光镜、电镜及MTS-810试验机对焊缝的组织及性能进行了分析,结果表明,采用Al-Mg焊丝焊接时,熔池中Al—SiC间的界面反应程度均较大.生成了较多的针状Al4C3,且Al4C3的尺寸较大。采用Al-Si焊丝时,MIG焊熔池中的界面反应程度显著降低,仅生成了少量尺寸较小的针状Al4C3;利用Al—Si焊丝还可有效地防止焊缝熄弧处的宏观结晶裂纹。力学性能试验表明,用Al-Si焊丝焊接的接头强度比用Al—Mg焊丝焊接的接头强度高。 相似文献
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采用Al-Mg及Al-Si两种焊丝分别对SiCp/6061Al复合材料进行了MIG焊及脉冲MIG焊,利用光学显微镜、电子显微镜及MTS-810试验机对焊缝的组织及性能进行了分析.结果表明,采用Al-Mg焊丝焊接时,无论是MIG焊还是脉冲MIG焊,熔池中Al-SiC间的界面反应程度均较大,生成了较多的针状Al4C3,且Al4C3的尺寸较大.采用Al-Si焊丝时,MIG焊熔池中的界面反应程度显著降低,仅生成了少量尺寸较小的针状Al4C3;而采用Al-Si焊丝的脉冲MIG焊焊缝中没有发现针状Al4C3.同时,利用Al-Si焊丝可有效地防止焊缝熄弧处的宏观结晶裂纹.力学性能试验表明,采用同样焊丝时,脉冲MIG焊接头的强度及伸长率比MIG焊接头的高,而用Al-Si焊丝焊接的接头强度比用Al-Mg焊丝焊接的接头强度高. 相似文献
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采用Al-Mg及Al—Si两种焊丝分别对SiCp/6061Al复合材料进行了MIG焊及脉冲MIG焊,利用光学显微镜、电子显微镜及MTS-810试验机对焊缝的组织及性能进行了分析。结果表明,采用Al—Mg焊丝焊接时,无论是MIG焊还是脉冲MIG焊,熔池中Al-SiC间的界面反应程度均较大,生成了较多的针状Al4C3,且Al4C3的尺寸较大。采用Al-Si焊丝时,MIG焊熔池中的界面反应程度显著降低,仅生成了少量尺寸较小的针状Al4C3;而采用Al—Si焊丝的脉冲MIG焊焊缝中没有发现针状Al4C3。同时,利用Al—Si焊丝可有效地防止焊缝熄弧处的宏观结晶裂纹。力学性能试验表明,采用同样焊丝时,脉冲MIG焊接头的强度及伸长率比MIG焊接头的高,而用Al-Si焊丝焊接的接头强度比用Al—Mg焊丝焊接的接头强度高。 相似文献
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本文以5wt%Al3Zr/铝基复合材料为研究对象,以Ar气体为离子气体,Al-Ti-B为丝材进行等离子焊接。用电化学综合测试仪测定了焊接区在3.5%NaCl溶液中的腐蚀极化曲线。采用扫描电子显微镜(SEM)、X射线衍射仪(XRD)对复合材料及其焊缝的组织和相组成进行了分析和表征,研究了Al3Zr/Al基复合材料等离子焊接后在3.5%NaCl溶液中的腐蚀行为和腐蚀机理。SEM分析结果表明,等离子弧焊接可获得较好的焊缝组织,焊缝组织主要由Al3Ti相和Al基体组成,Al3Ti相呈条状和球形。电化学极化曲线表明,材料在熔核处的耐蚀性略低于母材,焊缝处浸泡腐蚀机理为Al3Ti相和基体相的电极电位不同形成原电池反应造成。 相似文献
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《Science & Technology of Welding & Joining》2013,18(2):164-171
AbstractThe joint of Al 5A06 and aluminised Ti–6Al–4V dissimilar alloys was achieved by means of tungsten inert gas arc welding brazing. The effect of aluminized coating on the spreading behaviour of filler metal on Ti substrate was studied. The spreadability of liquid filler metal on the Ti substrate was enhanced obviously due to the presence of aluminised coating. The interfacial reaction layer was characterised by a uniform lamellar layer of TiAl3 intermetallic, with a thickness of 1 μm. Sound joints with well appearance were obtained, and the optimised tensile strength of the joint reached 216 MPa. The failure initiated from the interfacial layer at the root face and then propagated within the weld seam at the upper part of the joint. Capable welding parameters were broadened by the presence of aluminised coating for dissimilar metal joining of Ti/Al. 相似文献
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Influence of filler wire composition on weld microstructures of a 444 ferritic stainless steel grade
V. Villaret F. Deschaux-Beaume C. Bordreuil S. Rouquette C. Chovet 《Journal of Materials Processing Technology》2013,213(9):1538-1547
Seven compositions of metal cored filler wires for gas metal arc welding (GMAW), containing the same weight percent of chromium (Cr) and molybdenum (Mo) as 444 steel, but with different titanium (Ti) and niobium (Nb) contents were investigated. Experimental results pointed out that the filler wire Ti content required to be twice time more than the amount expected in the deposited metal. This was due to the low Ti transfer ratio during arc welding. Moreover, Ti increased the wetting angle and promoted penetration. It was supposed that Ti affected the weld pool surface tension what led to inward Marangoni convection.Columnar to equiaxed grain transition (CET) was also promoted thanks to the precipitation in the weld pool of Ti rich refractory compounds which act as heterogeneous nucleation sites for equiaxed grains. A minimum 0.3% Ti was required in the filler wire to form a completely equiaxed grain structure in the fusion zone. Niobium in the filler wire did not seem to have any effect on penetration, wetting and grain structure of the fusion zone. 相似文献
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1 INTRODUCTIONDiscontinuously(particle,whiskerandshortfiber)reinforcedaluminumalloycompositeshavebecomeanattractivestructuralmaterialformanyindustrialfieldsowingtoitsexcellentproperties(e.g.highspecificstrength,highspecificstiffnessandgoodwearresistance)… 相似文献
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研究了Sc,Zr元素对新型Al-Mg合金焊接接头组织和性能的影响。建立了MIG电弧二维数值分析模型,模拟出电弧温度场的分布情况,电弧最高温度超过20 000 K,且温度分布存在较大的温度梯度,说明高温电弧对合金有益元素有一定的烧损作用。采用合金元素不同的焊丝ER5356,ER5B06和ER5B71作为填充材料,对2 mm厚新型Al-Mg合金进行MIG焊接试验,研究高Mg焊丝添加不同稀土元素对焊接性能及组织的影响。结果表明,使用3种焊丝均可获得性能优良的焊接接头,使用ER5B06焊丝的接头力学性能得到一定提升,但焊缝晶粒细化效果不明显;使用复合添加Sc,Zr微量元素的ER5B71焊丝,接头晶粒能够有效细化,力学性能进一步得到提升。3种焊丝中,采用ER5B71焊丝的焊接接头强度最高,焊接系数为83%,焊接接头中起到细化晶粒作用的析出相以Al3(Sc,Zr)为主。同时,无论采用哪种焊丝,焊接热影响区未发生明细的晶粒粗化,说明在母材中加入一定的Sc,Zr微量元素,可提升合金材料抗软化能力,有效抑制热影响区再结晶行为。
创新点: 采用电弧物理数值模拟和进行试验结合的方法,进行研究论证,使研究内容充实,有理论深度,更具说服力;选择具有稀土元素的铝合金和焊丝作为研究对象,对新材料及焊材的研发具有一定指导意义。 相似文献
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Dissimilar metal joining of aluminum alloy to galvanized steel with Al-Si, Al-Cu, Al-Si-Cu and Zn-Al filler wires 总被引:8,自引:0,他引:8
Honggang Dong Wenjin HuYuping Duan Xudong WangChuang Dong 《Journal of Materials Processing Technology》2012,212(2):458-464
Aluminum alloy sheets were lap joined to galvanized steel sheets by gas tungsten arc welding (GTAW) with Al-5% Si, Al-12% Si, Al-6% Cu, Al-10% Si-4% Cu and Zn-15% Al filler wires. Different amounts of Si, Cu and Zn were introduced into the weld through different filler wires. The effects of alloying elements on the microstructure in the weld and tensile strength of the resultant joint were investigated. It was found that the thickness of the intermetallic compound (IMC) layer decreased and the tensile strength of the joint increased with the increase of Si content in the weld. The thickness of the IMC layer could be controlled as thin as about 2 μm and the tensile strength of the dissimilar metal joint reached 136 MPa with Al-12% Si filler wire. Al-Si-Cu filler wire could result in thinner interfacial layer than Al-Cu filler wire, and fracture during tensile testing occurred in the weld for the former filler wire but through the intermetallic compound layer for the latter one. A Zn-rich phase formed in the weld made with Zn-15% Al filler wire. Moreover, the Zn-Al filler wire also generated thick interfacial layer containing a great amount of intermetallic compounds and coarse dendrites in the weld, which led to a weak joint. 相似文献
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Chen ShujunWang XuanYuan TaoLi Xiaoxu 《金属学报》2018,(12):1735-1744
Magnesium alloys has a wide application prospect due to their good properties, such as high specific strength and specific stiffness, but the susceptibility of liquation cracking is also pretty high. The liquation in partially melted zone of AZ-series magnesium alloys were investigated with circular-patch welding test. The AZ91, AZ31 base alloys were welded with AZ61 and AZ92 filler wires by using the cold metal transter metal inert-gas (CMT-MIG) welding. The results show that, the liquation occurred along the weld edge of AZ91 with the eutectic reaction occurring between gamma(Mg17Al12) phase and Mg-rich phase. The liquation susceptibility of AZ31 was pretty low as gamma(Mg17Al12) was not present in base metal of AZ31. Meanwhile, a new method for predicting liquation cracking based on binary phase diagram was proposed. When the initial solidification temperature of weld is higher and the solidification temperature range of weld is shorter than those of base metal, the liquation crack susceptibility of weld is mostly higher. When the initial solidification temperature of weld is close to or below that of base metal, and the solidification temperature range of weld is close to or longer than that of base metal, the liquation cracking susceptibility of weld is lower. This method worked well on predicting the effect of composition of base metal and filler wires on liquation cracking, and the predicting results are consistent with the experimental results. That is, the liquation cracking susceptibility is higher with AZ91 base metal used than that with AZ31 base metal. And, the liquation cracking susceptibility is lower with AZ92 filler wire than that with AZ61 filler wire. 相似文献