时效处理对粉末高温合金惯性摩擦焊接头室温拉伸行为的影响

对惯性摩擦焊扩散连接的FGH96合金试样经时效处理前后的室温拉伸行为进行了研究，并对其失效机制进行了评估。结果表明，对于焊接态（原状态）FGH96合金试样，由于焊缝区和热影响区的γ′相综合强化效果弱，晶界平直化，导致焊缝区和热影响区的强度低于基体，在室温拉伸过程中塑性应变量大；由于热影响区的晶粒尺寸大，晶界强化效果弱，且位错强化效果低于焊缝区，使热影响区成为整个试样强度的最薄弱区域，裂纹从该处萌生，断口表现出一定的塑性特征。对于时效处理后的FGH96合金试样，由于γ′相的粗化，强化相体积分数的提高，及γ′/γ之间错配度的增加，提高了γ′相的综合强化效果，使焊缝区和热影响区的强度较焊接态试样显著提高，并高于基体，在室温拉伸过程中基体的塑性应变量相对较大。连续或半连续析出的M₂₃C₆型碳化物弱化了焊缝区晶界的结合强度，导致试样从该处断裂，并出现了脆性断裂的特征。显微硬度的测试结果较好验证了焊接态和时效态试样强度的分布情况。

Effect of aging treatment on the behavior of room temperature tensile of P/M superalloys used for inertia friction welding joints

The behavior of the room temperature tensile of the FGH96 P/M superalloys connected by the inertia friction welding before and after the aging treatment was investigated,and the failure mechanism of the FGH96 P/M superalloys was evaluated.The results show that,for the FGH96 P/M superalloy samples in the as-welded(original)state,the strength of the superalloy samples in the welding line zone(WLZ)and the heat affected zone(HAZ)is lower than that of the parent alloys,and the plastic strain is the largest during the room temperature tensile process,due to the weak comprehensive strengthening effect ofγ′phase and the straight grain boundaries in WLZ and HAZ.Because of the large grain size in HAZ,the weak strengthening effect of grain boundaries,and the lower dislocation density than that of WLZ,the strength of the superalloy samples in HAZ becomes the weakest,where the cracks originate and show a certain plastic characteristic of the fracture.For the FGH96 P/M superalloy samples after the aging treatment,the comprehensive strengthening effect ofγ′phase is improved,due to the coarsening ofγ′phase,the increase of the strengthened phase volume fraction,and the mismatch increase betweenγandγ′,compared with the superalloy samples in the as-welded state,the strength of the superalloy samples after the aging treatment in WLZ and HAZ is higher than that of the parent alloys,and the plastic strain of the parent alloys is larger during the room temperature tensile process.The M23C6 carbide precipitated continuously or semi-continuously weakens the bonding strength of grain boundary in the as-welded state,leading to the sample fracture and showing the characteristic of brittle fracture.The results of microhardness test verify the strength distribution of the FGH96 P/M superalloy samples in the as-welded state and after the aging treatment.