Influences of Pulse Shaping on Single-Track Clad of AISI316L Stainless Steel by Laser Material Deposition

Abstract

As a very common type of laser additive manufacturing technology, laser material deposition (LMD) is widely used, having exceptional application advantages including surface enhancing, repairing damaged parts with high value-add, and building functionally graded material. At present, the continuous wave laser is a common laser mode used in the LMD process. The investigation of pulse shaping, which can add a degree of control over the thermal history, is limited. In this study, the effects of pulse shaping on the geometrical characteristics, microstructure, and microhardness were investigated through conducting single-track experiments with different laser shapes, including continuous, rectangular, ramp up, ramp down, and hybrid ramp. The results indicated that the clads created by continuous and ramp up laser shape presented the maximum and minimum dimensions of geometrical characteristics, respectively. The rectangular and hybrid ramp laser shape deposited the clads with similar dimensions. The continuous laser shape produced the clad with the coarsest microstructure and lowest hardness because of the lowest cooling rate. The smallest grain size and highest hardness presented in the clad were seen with the rectangular laser shape owing to the biggest cooling rate. The cooling rates in ramp up and ramp down were restrained by the gradual heating and gradual cooling, respectively.

A Review on Laser Beam Shaping Application in Laser‐Powder Bed Fusion

“…For instance, L‐PBF systems utilizing ultrashort pulsed lasers may not require high average powers comparable to CW laser systems, thereby potentially reducing the power requirements for SLMs. [ 113,114 ]…”

“…[112] Research indicates that temporal beam shaping is vital for optimizing heat input, minimizing thermal gradients, and mitigating undesirable effects such as spatter or microcracking during laser-material interaction in pulsed laser AM processes. [113][114][115][116] Additionally, the combination of spatial and temporal beam shaping could be leveraged to achieve dynamic temporal beam shaping for specific applications. [117] While spatial and temporal beam shaping offer significant benefits, it is important to note that this review focuses solely on continuous wave (CW) laser beam shaping.…”

“…For instance, L-PBF systems utilizing ultrashort pulsed lasers may not require high average powers comparable to CW laser systems, thereby potentially reducing the power requirements for SLMs. [113,114] Another key consideration is the initial investment cost. Simple setups utilizing lenses tend to be more affordable.…”

A Review on Macroscopic and Microstructural Features of Metallic Coating Created by Pulsed Laser Material Deposition

“…X. Wang et al investigated the effect of different pulsed laser shape, including continuous, rectangular, ramp up, ramp down, and hybrid ramp, on the hardness of AISI316L deposition. They pointed out that the deposition created by rectangular laser shape presented highest hardness because of the minimum value of grain size caused by the high cooling rate as shown in Figure 8 [ 29 ].…”

Macroscopic and Microstructural Features of Metal Thin-Wall Fabricated by Laser Material Deposition: A Review

“…Based on the first layer, the new layer can be deposited through creating metallurgical bonding with the first layer along the scanning path. Similar process, in which the latter layers are sequentially created on the former layer, repeats again and again that makes the three-dimensional (3D) part to be built layer-by-layer [26][27][28][29][30].…”