激光高温化学复合加工GH4049合金化学液筛选研究

Research on chemical solution screening of GH4049 alloy of laser chemical hybrid processing at high temperature

针对纳秒激光微孔加工中存在重铸层、微裂纹和热影响区等问题,为提高微孔加工质量,提出激光高温化学复合加工的方法.首先探究化学液的成分与配比对微孔质量的影响,筛选出最佳的化学液配比.然后采用波长为1064 nm的纳秒激光器,对GH4049镍基高温合金进行激光高温化学复合加工.研究表明,在酸性环境中Cl-的氧化性更强,高温环境下可提高含有Cl-的化学液与氧化物、重铸层的反应速度.对比实验证明,与空气中直接打孔相比,激光高温化学复合加工可降低重铸层厚度、减少孔口熔融物堆积,减小微孔锥度,提高微孔的质量.因化学液具有一定的高温选择性,在高温环境可选择性与孔内重铸层反应,且具有冷却作用和局部微流动性,可带走加工区域的部分热量与残渣碎屑,从而降低孔口重铸层以提高微孔质量.

In order to solve the defects such as recast layer,micro-crack and heat-affected area in nanosecond laser hole machining,and improve the quality of microporous machining,a method of chemical hybrid processing at laser high temperature was proposed.Firstly,the influence of composition and ratio of chemical liquid on the quality of micro-pores was investigated,and the optimal ratio of chemical liquid was selected.Nanosecond laser with wavelength of 1064 nm was used to perform laser high temperature chemical composite processing on nickel-based superalloy GH4049.The results show that Cl-is more oxidizable in acidic environment,and the reaction rate with oxide and recast layer can be improved at high temperature.And the results were compared with those of air drilling.Comparative experiments show that composite machining can reduce the thickness of recast layer,orifice melt accumulation,and taper of micro-pores,and improve the quality of micro-holes.Because the chemical solution has a certain high temperature selectivity,it can selectively react with the recast layer in the hole at high temperature,and has the cooling effect and fluidity,which can take away the heat and residue debris in the processing area,so as to remove the recast layer and improve the quality of the micro hole.