An Overview of DLD
for AM: Part 2
Abstract
It's important to
determine the mechanica props.
of parts fabricated via LBAM
to predict performance while in service
1. Intro
DLD nozzle feed rates can be regulated to
generate materials w/ distinct microstructural
props. and chemical compositions [26]
DLD
features
nozzle feed rates can be regulated to
generate materials w/ distinct microstructural
props. and chemical compositions [26]
high deposition rates & a relative wide process
window too fabricate larger items relative
to the othermetal-based AM methods [57]
great tool for repatiring
high-value components[56]
Disadvantages of using
DLD for AM or repair [57]
relatively low
powder efficiency
rouger, post-DLD
surface finishes
Although the breadth of this article (Part II) is relatively broad, it is by no means comprehensive, as discussion on off the following efects are not included:
powder size
& morphology
multi-material
processing, etc.
2.2. Process Parameters
4. Process Optimization for
enhanced mechanical props.
5. Process Control
6. Conclusions
The inter-related relationships among process parameters, thermal history, microstructure, and fatigue behavior of DLD components are presented schematically in Fig. 22.
The complex thermal history of the deposited part
governs solidification, and consequently, the resultant
microstructure
porosity
residual stress formation
Mechanical properties, especially fatigue resistance, are extremely sensitive to microstruc- ture, porosity, and residual stress within DLD components.
Therefore, microstructure sensitive fatigue models, relating the microstructural features to fatigue resistance of material, can be readily employed to predict the fatigue life of DLD parts.
Such analytical models can be complemented
by using finite element analysis (FEA)
in which critical elements with higher stresses/strain
and possibility of fatigue failure can be determined.