表面纳米化对GH4049镍基高温合金性能的影响

Effects of Surface Nanocrystallization on the Properties of GH4049 Nickel-base Superalloys

超声喷丸(USSP)处理工艺在GH4049镍基高温合金表面制备出了纳米表面晶层,分析了不同超声喷丸强度和喷丸时间对其屈服强度、抗拉强度、显微硬度的影响,并通过试验分析了经表面纳米化后试件的残余应力分布。研究结果表明,喷丸时间的增加对材料强度的提高无直接关系,且随喷丸时间的增长,由于材料表面的损伤,会使材料的强度降低。经超声喷丸处理后,显微硬度较未处理试件明显提高,试件表面形成大约0.2mm厚度的压应力层,最大压应力远超过材料的屈服极限δs。

By means of ultrasonic shot peening （ USSP ） treatment, a nanostructured surface layer （ i. e. generation of a surface layer of nanostructures） was formed on a GH4049 nickel-base superalloys. The effects of different USSP processing time and amplitude of vibration on the properties （such as yield strength, strength and surface hardness） of samples tested were analyzed. In addition, the residual stress field of tensile partial specimen after shot peening was also researched. The experimental results indicate that the increase of yield strength and tensile strength of samples have no direct relation with the increment of treatment duration, and the strength will decrease with the increment of USSP processing time because of the surface damage of the material After the ultrasonic shot peening treatment, the surface micro：hardness of sample is effectively enhanced contrast to the untreated samples. A residual compressive stress layer of about of 0.2mm thick is formed and the maximum compressive stress is much larger than the yield strength