(1. 中南大学 材料科学与工程学院，长沙 410083；
2. 湖南人文科技学院 材料工程系，娄底 417000)
摘 要: 利用ANSYS有限元数值模拟研究镍基高温合金激光近净成形中沉积方向(单层10道(0o方向)、斜对角10道(12o方向)、单道10层(90o方向))对第一道的热影响规律，并结合实验对模拟结果进行进一步的验证。结果表明：沉积单道10层对第一道的热影响最大。随着层(道)数增加，3个沉积方向的温度梯度均减小，单层10道方向与斜对角10道方向减小趋势相同；熔覆过程中第一道上中心点应力σx由压应力逐渐转变成拉应力，并且沉积单层10道时第一道上的拉应力数值最大。观察镍基合金Inconel 740成型后的组织发现，柱状晶的生长方向从下到上呈外延生长特征并略偏向于材料沉积方向，与模拟结果一致。
关键字: 数值模拟；镍基高温合金；激光近净成形
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Materials Engineering Department, Hunan University of Humanities Science and Technology, Loudi 417000, China）
Abstract:The thermal influences of deposition direction(Single layer and 10 tracks (0° direction), diagonal 10 tracks (12° direction), single track and 10 layers (90° direction)) on the first track in the laser engineered net shaping of nickel-based superalloy were studied by ANSYS finite element numerical simulation, and the simulation results were further validated by experiments. The results show that the deposition of single track and 10 layers has the greatest impact on the first track. As the number of layers (tracks) increasing, the temperature gradients in the three directions decrease, and the decrease trend of the single track and 10 layers direction is same as that of the diagonal 10 tracks direction. During the cladding process, the stress σx on the first center is gradually converted from compressive stress to tensile stress, and the maximum tensile stress is obtained on the first track when the monolayer 10 tracks is deposited. Observation of the microstructure of nickel base alloy Inconel 740 after forming indicates that the growth direction of columnar crystals is characterized by epitaxial growth from bottom to top, and slightly inclines to the direction of material deposition which is in good agreement with the simulation results.
Key words: numerical simulation; nickel based superalloy; laser engineered net shaping
