脉冲激光熔覆成形变半径FeCrNiCu合金圆筒工艺及力学性能

The process and mechanical properties of FeCrNiCu alloy cylinder with variable radius by pulsed laser cladding forming

摘要:

针对激光立体成形变半径圆筒件边部及外沿塌陷、热累积效应引起力学性能下降等增材制造难点，提出了脉冲激光成形FeCrNiCu合金圆筒件优化路径及工艺，实现了变半径圆筒结构的直接熔覆成形，验证了该结构件良好的组织构成以及力学性能。试验结果表明：覆层顶部为细小致密的等轴晶组织，中部由具有定向生长趋势的树枝晶构成，底部由胞状晶构成，晶内及晶间有颗粒状Cr7C3型强化析出相析出。覆层显微硬度最高值为675HV0.1，覆层显微硬度主要分布在554~576HV0.1；成形层(纵向)的抗拉强度最大为1070MPa，抗拉强度范围1010~1070MPa；成形层(横向)的抗拉强度最大为860MPa，抗拉强度范围780~960MPa。覆层冲击韧性分布在511~727.5kJ?m-2，相关力学试验验证了该结构件具有优良的力学性能。

Abstract:

Aiming at the outer and edge collapse of the variable radius cylinder by laser cladding forming, the decrease of the mechanical properties caused by the thermal accumulation effect. The optimized path and process of FeCrNiCu alloy cylinder by pulsed laser forming was put forward, the direct cladding forming of the variable radius cylinder structure was realized, the good structure and mechanical properties of the structure were verified. The experiment results show that, the top of the forming layer is fine and dense equiaxed crystal structure, the middle of the forming part is composed of dendrites with a certain directional growth trend, the bottom of the forming part is composed of cellular crystal, and there are granular Cr7C3 enhanced precipitated in and between the crystals. The highest microhardness of the coating is 675HV0.1, and the microhardness of the coating is mainly distributed in 554 ~ 576HV0.1. The maximum longitudinal tensile strength of the forming layer is 1070 MPa, and the tensile strength is range from 1010 to 1070 MPa, the maximum transverse tensile strength of the forming layer is 860 MPa, and the tensile strength is range from 780 to 960 MPa. The impact toughness distribution of the coating is 511 ~ 727.5 kJ?m-2, the excellent mechanical properties of the forming part were verified by the relevant mechanical experiments.