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激光修复试样由激光修复区、热影响区和锻件基体区组成。修复区由贯穿多个熔覆层呈外延生长的粗大β柱状晶组成,柱状晶内为编织细密的网篮组织,α相的尺寸极其细小。热影响区组织由基体的锻造双态组织向修复区组织过渡。修复试样经600℃,1 h炉冷退火后,β柱状晶晶界连续性基本没有受到影响,晶内α板条略有长大,长宽比减小。退火前后修复试样显微硬度测试结果表明,退火态试样各区显微硬度相比沉积态均略有增加,增幅仅5%。退火后修复试样的高温拉伸性能和高周疲劳性能结果显示,拉伸性能强度指标高于模锻件标准,塑性与模锻件标准相当。修复试样疲劳极限为295 MPa,达到Ti17模锻件标准的70%,并对其在不同加载模式下的失效行为和断裂机制进行了分析。
Laser repair of the sample from the laser repair area, heat affected zone and forging matrix area. The repair area consists of coarse β columnar crystals that have been epitaxially grown through multiple layers of cladding. The columnar grains are closely woven baskets and the size of the α phase is extremely small. Heat affected zone tissue from the matrix forging bimodal tissue repair area organization transition. After the samples were annealed at 600 ℃ for 1 h, the continuity of β-columnar grain boundaries was basically unaffected. The α-laths grew slightly and the aspect ratio decreased. The results of the microhardness test before and after annealing show that the microhardness of the annealed samples increases slightly by 5% compared with the deposition state. The high temperature tensile properties and high cycle fatigue properties of the repaired samples after annealing show that the tensile strength index is higher than that of die forgings, and the plasticity is comparable to that of die forgings. The fatigue limit of the repaired specimen was 295 MPa, which reached 70% of the standard for Ti17 die forging. The failure behavior and fracture mechanism under different loading modes were analyzed.