W-(Ni-Cr-Fe-Si-B)混合粉末中間層真空擴散釬焊連接鎢與鋼

W-(Ni-Cr-Fe-Si-B)混合粉末中間層真空擴散釬焊連接鎢與鋼Vacuum diffusion brazing bonding tungsten to steel using W-(Ni-Cr-Fe-Si-B) mixed powders interlayer

以高能球磨態(tài)90W-10(Ni-Cr-Fe-Si-B)(質(zhì)量分數(shù)，%)混合粉末為釬料中間層，分別采用1000、1050和1100 ℃，均保溫60 min并加壓5 MPa的工藝參數(shù)，對純鎢(W)和0Cr13Al鋼進行真空擴散釬焊連接。利用激光粒度分析儀、SEM、EDS和電子萬能試驗機等研究混合粉末形態(tài)、接頭的微觀組織、成分、力學性能及斷口特征。結(jié)果表明：接頭中的混合粉末中間層通過液相燒結(jié)過程，實現(xiàn)鎢與鋼的擴散釬焊連接，并在接頭中生成均勻致密的鎢基高密度合金層。高能球磨制備混合粉末對鎢基高密度合金層壓力下的均勻化與致密化生成具有關鍵作用。連接溫度越高，鎢基高密度合金層的液相燒結(jié)組織特征越明顯。鎢/鋼接頭剪切強度在125~130 MPa之間，斷裂均發(fā)生在鎢基高密度合金層/鎢母材的結(jié)合區(qū)，斷口主要呈現(xiàn)為鎢母材的脆性沿晶斷裂和鎢基高密度合金層粘結(jié)相與鎢顆粒相的韌性脫離斷裂。

Vacuum diffusion brazing between tungsten (W) and 0Cr13Al steel using 90W-10(Ni-Cr-Fe-Si-B) (mass fraction, %) powder mixture interlayer prepared by high energy ball milling, was carried out with 5 MPa at 1000, 1050 and 1100 ℃ for 60 min, respectively. The morphology of powder mixture was studied by laser particle size analyzer and SEM. The microstructures, composition and fracture characteristics of the joints were studied by SEM, EDS and the shear strength of the joints were tested by electronic universal testing machine. The results show that the tungsten heavy alloy layer forms on the tungsten matrix through 90W-10(Ni-Cr-Fe-Si-B) mixed powder liquid phase sintering, and good bonding between tungsten and steel is realized based on diffusion brazing mechanism. High energy ball milling plays key role in densification and homogenization of tungsten heavy alloy layer. At higher bonding temperature, the liquid phase sintering microstructure characteristics of the tungsten heavy alloy layer is more obvious. The shear strength of joints is between 125-130 MPa. The fractures all occur near the interface of tungsten matrix and tungsten heavy alloy layer, the former fracture is brittle intergranular fracture, while the latter fracture is ductile interface debonding fracture between tungsten phase and Ni-rich phase.

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