## 3 Results
### MAM Technologies  
A laser source is utilized to fuse metallic powder, making it one of the most commonly used AM techniques, which is shown in Figure 6, from the Systematic literature review. It is an automated method for producing complicated metal components straight from Computer-Aided Design (CAD) files by fusing metal powders. It does not require the removal of any binder, and in theory, any castable material can be used in the SLM process [60].  
The Laser Powder Bed Fusion (LBPF) technique utilizes a high-density laser as a heat source to melt-fuse metallic powder into relatively close products with superior relative density and resolution. Modern laser sources like Nd: YAG, Yb: YAG, Yb: Fiber, and excimer gas lasers have substantially enhanced the precision and quality of AM components. This advancement in laser technology has increased the LBPF's energy efficiency, allowing for appropriate laser power, scanning speed, layer thickness, hatch spacing, etc. to be used during sample printing. The enhanced LBPF version reduces macro-and microstructural  
Figure 5: (**a**) shows the three unit cell topologies used in specimens in this study, OT, RT, RTN. Each of the three unit cell topologies has relative density (\(\rho^{*}\)) of 30% (**b**) shows the five hybrid lattice structure configurations examined in this study. The built plate of each specimen type is noted so that build orientation can be considered in this analysis. Reprinted with permission from ref. [59]. 2021, Elsevier.  
flaws like balling, porosity, keyholes, and material evaporation in the final printed components. Reduced material flaws and the ability to print a wider spectrum of materials, such as copper, aluminum, and tungsten, would boost manufacturing efficiency. LBPF uses powder rather than wire material due to its higher laser penetration. Titanium alloys are expensive, and common ways to make them, like casting, forging, and machining, make them even more expensive [61].  
However, proper process parameter selection is critical for operational success. Nonetheless, the strong temperature gradient caused by quick solidification following laser melting may result in residual strains and cracks. Typical flaws are pores caused by early powder contamination, evaporation, or local voids, following powder-layer deposition in the absence of fusion flaws. Defects are the primary problem regarding the fatigue performance of SLM components. Efforts are underway to optimize the SLM process parameters and to define acceptable thermo-mechanical post-sintering treatments [62].  
WAAM feeds a wire at a regulated rate into an electric or plasma arc to melt the wire onto a substrate or previously placed layer. WAAM features a better material deposition rate, lower cost, and no powder handling requirements than laser or electron beam powder-based AM. Raw WAAM products have poor dimension and surface accuracy, requiring post-process machining. Material waste and machining costs are reduced for costly and difficult-to-machine high-strength titanium alloys.  
Qualification and certification of service performance is a difficulty for using additive manufacturing to create safety-critical structural elements. Microstructure changes and process-induced residual stress alter WAAM-deposited components' mechanical characteristics [63]. Widespread AM platforms have been proposed for repair based on DED technologies that utilize melting powder or wire feed with laser or EB energy sources to add material layer by layer to refurbish damaged components. DED technologies have advanced significantly for dimensional restoration [64]. However, fatigue-critical repairs are still in the development or qualifying phase, owing to the lack of performance data and poor confidence scatterplots. EBAM revealed encouraging static and uniaxial fatigue performance.  
Figure 6: MAM Technologies.