超声振动及热处理对激光直接成形IN718高温合金组织及性能的影响

Effect of Ultrasonic Vibration and Heat Treatment on Microstructure and Mechanical Properties of Laser Direct Forming IN718 Superalloy

摘要:

研究了超声振动及热处理对激光直接成形IN718高温合金微观组织和拉伸性能的影响规律。结果表明：施加超声振动后,与沉积态相比,微观组织得到细化,显微硬度和拉伸强度得到提高；经均匀化+固溶+双极时效热处理后,柱状枝晶组织转变为等轴状再结晶组织,Laves相固溶消失,在晶界和晶内弥散析出颗粒状或细针状δ相,基体上析出大量γ″和γ′强化相,合金性能得到进一步改善,室温拉伸性能达到了锻件的技术标准Q/3B 548-1996(高强)。

Abstract:

The effects of ultrasonic vibration and heat treatment on the microstructure and tensile properties of laser direct forming IN718 superalloy were investigated. The results show that microstructural grain size became finer due to the actions and influences of ultrasonic vibration. In addition, the microhardness and tensile strength of the parts fabricated by LDF with ultrasonic vibration were higher compared with that of the ones fabricated by LDF without ultrasonic vibration. With the heat treatment of homogenization, solution and double aging, the columnar dendrites changed to equiaxed grains due to recrystallization. Laves phase dissolved, and there were grainy and acicular δ phase distributing in and along boundaries of the grains. Besides, a large number of strengthening phase γ″ and γ′ separated out on the matrixes. The room-temperature tensile properties of heat treatment samples reached the wrought standard of Q/3B 548-1996.