激光选区熔化成形因瓦合金点阵结构参数优化及其性能研究

Optimization of Process Parameters and Performances of Invar-Alloy Lattice Structures Manufactured via Selective Laser Melting

因瓦合金点阵结构能够集成低热膨胀系数和低密度的优势,在航空航天领域具有广泛的应用前景。激光选区熔化[SLM,又称激光粉末床熔融(L-PBF)]作为一种应用最为广泛的金属增材制造技术,在成形复杂点阵结构方面具有极大的优势,但是目前对SLM成形因瓦合金点阵结构的性能影响规律的认识还不够深入。采用三因子三水平设计正交试验来优化SLM成形因瓦合金工艺参数,并以抗拉强度和屈服强度为指标,提出了激光功率为280 W、激光扫描速率为1000 mm/s、扫描间距为0.12 mm的较优参数,此参数下成形试样屈服强度为340 MPa、抗拉强度为419 MPa。在优化参数基础上,探究了扫描速率对SLM成形因瓦合金点阵结构几何性能和力学性能的影响,发现激光功率为280 W、激光扫描速率为1000 mm/s、扫描间距为0.12 mm下成形的点阵结构兼具较好的力学性能和几何性能。

The lattice structure of invar-alloy offers the advantages of low thermal expansion coefficient and low density,thus rendering it extremely suitable for the aerospace industry.Selective laser melting(SLM),also known as laser powder bed fusion(L-PBF),is the most widely used metal additive-manufacturing technology and offers significant advantages in manufacturing complex lattice structures.However,our current understanding regarding factors that affect the performance of invar-alloy lattice structures fabricated via SLM is inadequate.Hence,a three-factor,three-level orthogonal experimental design was employed to optimize the SLM process parameters of invar-alloy.Using tensile strength and yield strength as indicators,we propose the following optimal parameters:laser power,280 W;scanning speed,1000 mm/s;and scanning spacing,0.12 mm.Tensile samples prepared under these parameters indicate yield and tensile strengths of 340 MPa and 419 MPa,respectively.Based on the optimized parameters,we investigated the effect of scanning speed on the geometric and mechanical properties of the invar-alloy lattice structure fabricated via SLM.The result shows that the lattice structure fabricated under a laser power of 280 W,a scanning speed of 1000 mm/s,and a scanning spacing of 0.12 mm exhibits both favorable mechanical and geometric performances.