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Additive Manufactured Beta-Titanium Alloys



























           Figure 3. A conceptual framework for predicting manufacturability for powder bed fusion using machine learning.

           also fabricated using  Ti24Nb4Zr8Sn and the samples   the input and output of L-PBF. Smaller data sets can
           have Young’s modulus of 0.95 ±  0.05  GPa [50] . Porous   be used to develop and train the machine learning
           lattice  structures  are also  fabricated  using  β-phase   algorithms by measuring the part quality from different
           Ti24Nb4Zr8Sn [51] .  Ti35Zr28Nb was used to fabricate   process  parameters.  Predictive  models  using genetic
           porous lattice structures with FCCZ and FBCCZ       programming and neural network modeling for process
           unit cells.  While the bulk material elastic modulus is   planning  purposes  have been developed for  L-PBF .
                                                                                                            [57]
           between 57.0 ± 1.8% GPa, the porous lattice structures   Deep neural networks can also be used to interpret and
           are able to achieve elastic modulus of between 1.1 ±   classify melt pool images that can be used to predict the
           0.1% GPa and 1.3 ± 0.1% GPa [52] . It was also concluded   defects during the process [58,59] . Shin et al. developed an
           that the structures have good corrosion behavior and   artificial neural network to identify the optimum L-PBF
           biocompatibility. Using Ti25Nb3Zr3Mo2Sn to fabricate   process parameters to obtain defect-free Ti5Al5V5Mo3Cr
           porous lattice structures by L-PBF, Liu  et al. found   (wt%) and showed the potential of using this approach to
           out that martensitic phase transformation takes place   reduce processing time and making the L-PBF process
           during yielding under compression loading for the   more cost effective . A conceptual framework on using
                                                                               [60]
           samples, which prevents the samples from layer-wise   machine learning to predict manufacturability for PBF is
           fracture [53] . Such phase transformation is also found to   shown in Figure 3.
           improve the tensile strength of  β-Ti alloys [54] . Using   Comprehensive  reviews on machine  learning  for
           EB-PBF, Liu  et al. fabricated porous structures made   AM are  available [56,61-63] .  Using  data-driven  artificial
           of Ti24Nb4Zr8Sn and compared the effect of different
           designed porosities [55] .                          intelligence, it is possible to predict and optimize process
                                                               parameters  that can  obtain  desired  part  properties [64,65] .
           3.3. Machine learning and artificial intelligence   Furthermore,  a conceptual  framework  that  combines
                                                               statistical analysis, mathematical modeling, and machine
           The  fluctuations  in  L-PBF  make  process  control  and   learning techniques has also been proposed .
                                                                                                   [66]
           prediction challenging. While physical simulations have
           been developed to provide deeper understanding of   4. Summary
           the process, it is still challenging for them to show the
           full  aspects  of  L-PBF.  Machine  learning  and  artificial   In this perspective  article,  the feasibility  of processing
           intelligence can be used to enhance and complement   β-Ti alloys using PBF has been shown using currently
           simulations in achieving higher part quality . The   available literature. It has been shown that these alloys
                                                   [56]
           current practice to obtain defect-free parts, or commonly   have potential  to be better candidates  for biomedical
           known as the process parameters optimization, involves   implants  due to their  lower elastic  modulus and high
           multiple  rounds  of  experiments  which  are  costly  and   mechanical  strength.  However,  to  realize  their  full
           time intensive. Machine learning techniques potentially   potential, future research in the area of new processing
           can be applied to establish relationships between   approaches and new designs are still needed.

           4                           International Journal of Bioprinting (2022)–Volume 8, Issue 1
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