DD5单晶高温合金大间隙钎焊的组织演变与界面形成机制

发布时间：2018-02-03 04:32

  本文关键词： 单晶高温合金 大间隙钎焊 混合粉末钎料 微观组织 力学性能　出处：《金属学报》2016年07期 　论文类型：期刊论文

【摘要】：采用新型Ni-Co-Cr-W-B+DD99混合粉末钎料焊接DD5单晶高温合金,分析钎料成分对接头显微组织演变和接头力学性能的影响,探讨Ni-Co-Cr-W-B钎料/DD99合金粉的界面形成机制与接头形成机理.结果表明,在钎焊过程中,Ni-Co-CrW-B钎料/DD99合金粉的界面上首先形成了g-Ni初生相,B偏析并析出细小颗粒状的M3B2型硼化物,在冷却过程中残余液相形成块状M3B2相、g+g′共晶相和g-Ni+Ni3B+Cr B共晶相.提高混合粉末钎料中DD99合金粉的配比,可有效抑制焊缝中的硼化物和低熔点共晶相的形成,提高焊缝成分和组织均匀性.当DD99合金粉的配比增加至70%(质量分数)时,B可均匀扩散至DD5母材和DD99合金粉中,未观察到低熔点共晶相,界面处脆性化合物相显著减少,接头高温性能提高.接头经过固溶处理和时效处理后,在870℃的高温拉伸性能可提高至1010 MPa.
[Abstract]:The welding of single crystal superalloy DD5 with Ni-Co-Cr-W-B+DD99 mixed powder solder, analysis of the effect of filler composition on microstructure evolution and mechanical properties of the joints of Ni-Co-Cr-W-B solder joints, /DD99 alloy powder interface formation mechanism and the formation mechanism of the joint. The results show that in the soldering process, Ni-Co-CrW-B /DD99 solder alloy powder on the interface of the first formed g-Ni primary phase B, segregation and precipitation of fine particle M3B2 type borides, during the cooling process of residual liquid phase formation of bulk phase M3B2, g+g 'g-Ni+Ni3B+Cr B eutectic phase and eutectic phase DD99 alloy powder. Improve the mixing ratio of solder powder, can effectively inhibit the weld of boride and low melting point eutectic phase formation, improve the weld microstructure and composition uniformity. When the DD99 alloy powder ratio increased to 70% (mass fraction), B can be uniformly diffused into the base metal of DD5 and DD99 in alloy powder, not observed At low melting point eutectic phase, the brittle compound at the interface is significantly reduced, and the high temperature performance of the joint is improved. The tensile properties of the joint at 870 degrees C can be increased to 1010 MPa. after solid solution treatment and aging treatment.

【作者单位】： 中国科学院金属研究所;
【基金】：国家自然科学基金项目51401210和51331005 国家高技术研究发展计划项目2014AA041701资助~~
【分类号】：TG132.3;TG454
【正文快照】： Manuscript received 2015-12-03,in revised form 2016-04-17DD5单晶高温合金是我国研制的第二代含Re镍基高温合金,具有优异的综合性能,作为高效气冷组合式叶片最关键的战略材料,已应用于具有更大推重比和更高热效率的在研航空发动机[1].由于先进航空发动机叶片在设计上采用，

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