(兰州理工大学 省部共建有色金属先进加工与再利用国家重点实验室，兰州 730050)
摘 要: 采用SEM、OM及XRD和压缩试验等手段，研究GH3625合金管材在冷塑性变形和退火热处理过程中位错密度和硬度的变化规律，探讨合金中孪晶的形态及其形成机制。结果表明：冷变形量是影响GH3625合金管材塑性变形机制的主要因素，ε＜0.05时，塑性变形以滑移变形为主，其主要硬化机制是位错强化；随着冷变形量的增加，合金的位错密度和硬度显著增加，组织中产生大量的形变孪晶，塑性变形方式由滑移主导的变形转变为以孪生为主导的变形，其主要的硬化机制是孪晶强化；随着退火温度的增加，GH3625合金管材的位错密度和硬度逐渐降低，退火孪晶的形态从中止型逐渐转变为穿晶型。GH3625合金管材在冷变形和退火过程中出现不同形态的孪晶，可分为中止型孪晶和穿晶型孪晶，前者的形成机理是不全位错按极轴运动的结果，后者形成的本质是层错。
关键字: GH3625合金；加工硬化；退火软化；形变孪晶；退火孪晶
（State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals, Lanzhou University of Technology, Lanzhou 730050, China）
Abstract:The evolution of dislocation density, hardness and microstructure of GH3625 superalloy tube during cold plastic deformation and annealing heat treatment were investigated by SEM, OM, XRD and compression test. And the morphology and formation mechanism of twin in the alloy were discussed. The results show that the cold deformation is the main factor which affects the plastic deformation mechanism of GH3625 superalloy. When true strain is less than 0.05, the plastic deformation is dominated by slip deformation, and the mechanism of work hardening is dislocation strengthening. With the increase of the cold deformation, dislocation density and hardness of GH3625 superalloy tube significant increase as well as a large amount of deformation twins appear in the microstructure, and the deformation mode changes from slip-dominated deformation to twin-dominated deformation, and the mechanism is twin strengthening. With the increase of annealing temperature, dislocation density and hardness of GH3625 superalloy tube gradually decrease, and the morphology of annealing twin changes gradually from suspended to transgranular. GH3625 superalloy tube in cold deformarion and annealing processs appears different morphologies of twin, it can be divided into suspended twin and transgranular twin which have different formation mechanisms in growth, the former is the motion of partial dislocations, the latter is the stacking faults mechanism.
Key words: GH3625 superalloy; work hardening; annealing softening; deformation twin; annealing twin
