固溶温度对激光立体成形GH4169高温合金组织和性能的影响

Effects of Solution Treatment Temperature on Microstructures and Properties of Laser Solid Forming GH4169 Superalloy

摘要:

研究激光立体成形GH4169高温合金固溶处理后的组织，分析了固溶过程中合金元素的均匀化，并对材料显微硬度的变化做了讨论。结果表明，随固溶温度的升高，材料的晶界越来越清晰，经1000-1170 °C固溶处理1 h后材料发生再结晶，当固溶处理温度高于1100 °C，有大量孪晶出现，晶粒相比沉积态显著细化，晶粒尺寸约200 μm。合金元素的均匀化在1100 °C保温1 h后基本完成。显微硬度测试结果显示，材料的显微硬度值随固溶温度的升高而降低，在固溶温度低于1100 °C时减小趋势较快，高于1100 °C时减小趋势减缓。显微硬度的变化与材料中g ′和g "相及d相的形态和数量有关。1100 °C是激光立体成形GH4169合金比较合适的固溶处理温度下限。

Abstract:

The effects of the solution treatment temperature on the microstructure, the chemical composition homogeneity and the microhardness of laser solid forming GH4169 superalloy were investigated. It is found that the grain boundaries become clearer with increasing of the solution treatment temperature. The recrystallization occurs when the samples are solution treated at 1000-1170 °C for 1 h; when the solution treatment temperature is higher than 1000 °C, a large number of twin crystals can be observed, and the grains are refined remarkably compared with the as-deposited grains. The chemical homogeneity can be achieved through solution treatment at 1100 °C for 1 h. With increasing of the solution treatment temperature, the microhardness first decreases rapidly, and then slowly when the solution treatment temperature is above 1100 °C. The variation of microhardness can be explained based on the precipitation behaviors of g ′, g " and d phases during the solution treatment. It is concluded that the temperature of 1100 °C is the low limit of solution treatment temperature range for laser solid forming GH4169 superalloy.