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0IntroductionInterlayer metal is usually introduced while solidwelding heterogeneous metals with different chemical com-ponents and microstructures[1-3].The diffusion activationenergy(DAE)in both sides of interlayer and base metalcould be affected by the … 相似文献
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分别选取500,530,560 ℃焊接温度,进行2A14铝合金真空扩散焊,保温时间为60 min,焊接压力为4 MPa,真空压力低于3.4×10-3 Pa.焊后用扫描电镜(SEM)观察接头的焊合率、界面和母材组织形貌.结果表明,在500 ℃固溶线以下温度进行2A14铝合金扩散焊时,主要是界面微区塑性变形破碎氧化膜,实现局部微量的金属之间连接,焊合率很低.温度继续升高到530 ℃,超过固溶线温度,但小于Al-Cu共晶温度时,增加了界面CuAl2相结合机理,焊合率有明显提高.焊接温度在Al-Cu共晶温度以上,达到560 ℃时,CuAl2相完全溶解并在晶界生成共晶液相.该液相挤压、破碎界面氧化膜,并填充界面微孔,焊接接头界面呈正弦波状界面形貌,因而焊合率显著提高.根据这一分析结果,建立了晶界液相生成与界面氧化膜的破碎模型. 相似文献
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Interfacial microstructure and properties of YG11C/42CrMo joint brazed with BCu64MnNi filler metal
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Brazing hard alloy to high strength steel, incomplete atomic diffusion and excessive brittle reaction product precipitation at the faying interface are usually suffered because of incomplete understanding the process of the initial interface disappearing and diffusion layer forming and evolving. In this paper, hard alloy YG11C (WC-11wt.%Co) and high strength steel 42CrMo were picked up as base metals and BCu64MnNi as filler metal to clarify the interfacial microstructure evolution. The process parameters of dwell time were set as 30s, 60s, 120s, and 300s and braze temperature were set as 950℃, 970℃, 990℃, 1010℃, the effect of which on the evolution of interfacial microstructure, tensile strength, integrated with fracture morphology analysis, were conducted. The results showed that increasing brazing temperature from 950℃ to 970℃, no significant difference existed in the joint interface, whereas brazed at 990℃, the binder phase erosion occurred, i.e. the liquid filler metal etched into Co binder phase of WC-Co base metal, which caused WC particles debonding from the base metal surface and formed an micro-anisotropic zone.. Increase temperature to 1010℃, severe binder erosion happened so as to micropores appear. Through the parameters optimization, the tensile strength can reach to the maximum 589MPa at temperature of 970℃. The dwell time showed similar effect on tensile strength because longer dwell time also caused erosion and porosity owing to long-time diffusion and reaction. 相似文献
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在10 MPa、60 min的工艺条件下,分别添加5μm、20μm的Ni箔或5μm的Ti箔为中间层,采用三种工艺方案对10μm纯Mo箔和20μm、60μm纯Al箔进行真空扩散连接。方案一:在550℃下加Ni箔中间层的直接扩散连接;方案二:先在900℃进行Mo-Ni扩散连接,然后在450~550℃进行Mo/Ni与Al的连接;方案三:550℃下加Ti箔中间层的直接扩散连接。利用扫描电镜(SEM)观察接头界面形貌,并对结合机理和相组成进行分析。结果表明,方案一的焊合率仅为3%。方案二实现了界面良好连接,焊合率达到89%~100%,在Mo-Al之间存在5层反应产物,自Mo侧依次为MoNi、残留Ni层、Ni_2Al_3、NiAl_3、Al-Ni固溶体;中间层Ni箔的厚度由5μm增加到20μm时,Mo-Ni扩散层变厚,焊合率达到100%。采用方案三,即添加5μm的Ti箔做中间层时,获得了良好的界面连接,焊合率达到100%。 相似文献
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基于材料物理、相平衡等领域的晶界相转变概念,借助瞬间液相扩散焊手段,以铜与不锈钢异种材料为研究对象,对铜-钢扩散焊接头中合金液相沿钢侧晶界的渗透现象进行初步探讨.结果表明,试验温度范围内,添加单质中间层时,钢侧结合界面均较平直;添加QSn6.5-0.1+Au复合中间层时,钢侧母材存在液相合金的晶间渗透现象,950℃高温时,晶间渗透作用充分且明显,由于近结合界面处Cu原子沿奥氏体晶界进行扩散的同时向晶粒内部扩散,从而近结合界面和远离结合界面处晶间渗透形貌存在差异,晶间残留的白色物质为含有少量Sn的CuAu合金. 相似文献
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