摘要:
采用粉状中间层合金D1P对镍基单晶高温合金DD3进行了TLP扩散焊,并对接头组织与性能进行分析研究.结果表明,D1P粉状中间层合金TLP扩散焊接头的焊缝主要由γ+γ'双相组织、枝状化合物(Mo,W,Cr,Ni)3B2和条状化合物(Cr,Mo)23(C,B)6组成,近缝区中存在块状或针状化合物相(Mo,W,Cr,Ni)3B2.接头中存在明显的组织不均匀现象,对接头性能具有明显的不利影响.接头组织不均匀现象可经过高温长时间保温消除,1 250℃/24 h/空冷扩散焊的接头,并在焊后进行时效处理,其980℃持久强度可达到母材的90%.
Abstract:
DD3 is a first generation nickel-based single crystal superalloy developed in China.In order to meet the possible need of manufacturing turbine blades and vanes, DD3 was TLP diffusion bonded with D1P powder interlayer alloy and the investigation on joint microstructure and properties was conducted.The results showed that, the bonding seam was mainly composed of γ+γ' two-phase matrix, dendritic compound was identified as(Mo, W, Cr, Ni) 3B2 and strip-like compound was identified as(Cr, Mo)23(C, B)6.Some blocky or needle-like compounds were precipitated in the zone adjacent to the bonding seam, and the TEM analysis results indicated that these compounds were identified as(Mo, W, Cr, Ni) 3B2 borides.Microstructural inhomogeneity existed in the joint along the flowing direction of molten interlayer alloy, and this inhomogeneity could not be eliminated even by the diffusion bonding for 24 h at elevated-temperature of 1 250℃.There are some γ' phases in the form of large block.The boundaries between these large γ' phases and the bonding seam matrix became the weak part of the joint, which damaged the joint property.Under proper bonding condition, the stress-rupture strength at 980℃ of the TLP diffusion bonded DD3 alloy joints reached 90% of that of the base metal.
百度学术
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