**3.4 Laser scan strategies on the morphology and formation of high entropy alloys**

The laser scan strategies are used to reduce residual thermal stresses and fill a single cross section that can be subdivided into smaller sectors with scan lines. The lines can follow patterns such as spiral, zigzag, parallel, chessboard or paintbrush. When the laser scan speed is reduced thermal gradients and solidification may lead to cracks, however, when the scan speed is increased, the power has to be increased, therefore, knowing the right scan strategy to use in fabricating high entropy alloys is important to achieve a homogeneous system.

The type of laser and the process parameters of a laser additive manufacturing technique are not included as the scan strategies. The scan strategies show a pattern that influences independent variables during the LAM process, therefore, the scan strategies must first be defined before another parameter optimization is achieved.

Scan strategies can be divided into the layer and vector scan strategies and these strategies not only control the properties of the material but also are an important factor used to control the grain location and texture of the high entropy alloy microstructure [35].

### *Aerodynamics*
