TC4添加调控激光熔化沉积GH4169合金组织与性能

Effects of TC4 Addition on Microstructure and Mechanical Properties of GH4169 Alloy Prepared by Laser Melting Deposition

摘要:

在常规GH4169合金粉末中添加TC4合金粉末，代替Al和Ti合金化，采用球磨合金化与激光熔化沉积技术制备了具有不同TC4含量的GH4169合金试样。研究了TC4添加及其含量对激光熔化沉积GH4169合金组织与性能的影响。结果表明，激光熔化沉积TC4/GH4169合金显微组织仍主要由粗大柱状晶构成，但柱状晶一次枝晶臂间距及晶粒尺寸降低，Laves相由连续长链状转变为弥散短棒状，长宽比由9.2下降至2.6，合金组织得到明显细化。TC4添加可有效代替Al和Ti合金化，沉积过程中TC4熔化，主要组成元素Ti和Al充分溶解到GH4169合金熔体，参与凝固及组织的形成，提升合金沉积熔池的凝固速率，减少元素偏析，促进强化相γ?和γ?析出，提高沉积态合金硬度与力学性能。激光熔化沉积GH4169合金中TC4添加可以起到细晶强化、固溶强化和析出强化作用。

Abstract:

GH4169 alloy samples with different TC4 contents were prepared using ball milling alloying and laser melting deposition by adding TC4 alloy powder to conventional GH4169 alloy powder instead of Al and Ti alloying. The effects of TC4 addition on microstructure and properties of GH4169 alloy prepared by laser melting deposition were investigated. The results show that TC4/GH4169 alloy is mainly composed of coarse columnar crystals, but the primary dendrite arm distance and grain size of the columnar crystals decrease. Besides, the Laves phase changes from continuous long chain to diffused short rod with the aspect ratio decreased from 9.2 to 2.6. During the deposition process, TC4 is melted, of which Ti and Al elements are released, then fully dissolved into GH4169 alloy melt, and finally participated in solidification and microstructure formation of the alloy. The addition of TC4 increases the solidification rate of the alloy deposition pool and reduces the segregation of elements in the solidification structure. Besides, the addition of TC4 promotes precipitation of γ? and γ? in the solidification microstructure. Thus, the hardness and mechanical properties of the deposited alloy are improved. The addition of TC4 shows effects of fine crystal strengthening, solid solution strengthening, and precipitation strengthening.