Virtual Development of Process Parameters for Bulk Metallic Glass Formation in Laser-Based Powder Bed Fusion.

Johan Lindwall,Anders Ericsson,Andreas Lundbäck,Jithin James Marattukalam

doi:10.3390/ma15020450

Johan Lindwall, Anders Ericsson + Show 2 more

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https://doi.org/10.3390/ma15020450

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Abstract

The development of process parameters and scanning strategies for bulk metallic glass formation during additive manufacturing is time-consuming and costly. It typically involves trials with varying settings and destructive testing to evaluate the final phase structure of the experimental samples. In this study, we present an alternative method by modelling to predict the influence of the process parameters on the crystalline phase evolution during laser-based powder bed fusion (PBF-LB). The methodology is demonstrated by performing simulations, varying the following parameters: laser power, hatch spacing and hatch length. The results are compared in terms of crystalline volume fraction, crystal number density and mean crystal radius after scanning five consecutive layers. The result from the simulation shows an identical trend for the predicted crystalline phase fraction compared to the experimental estimates. It is shown that a low laser power, large hatch spacing and long hatch lengths are beneficial for glass formation during PBF-LB. The absolute values show an offset though, over-predicted by the numerical model. The method can indicate favourable parameter settings and be a complementary tool in the development of scanning strategies and processing parameters for additive manufacturing of bulk metallic glass.

Highlights

We present an alternative method by modelling to predict the influence of the process parameters on the crystalline phase evolution during laser-based powder bed fusion (PBF-LB)
This study presents a method to assist the development of process parameters by simulation in laser-based powder bed fusion (PBF-LB) to benefit bulk metallic glass formation
The crystalline phase evolution is predicted for the different sets of process parameters

Summary

Introduction

This study presents a method to assist the development of process parameters by simulation in laser-based powder bed fusion (PBF-LB) to benefit bulk metallic glass formation. Simulation of different process parameters with this method enables the prediction of favourable parameters for bulk metallic glass formation. Metallic glass can be produced by rapid solidification of the molten metal to bypass crystallisation. The critical cooling rate can be reduced to about 10−1–103 Ks−1 for alloys with good glass-forming ability [2]. The conventional alloy AMZ4 Zr59.3Cu28.8Al10.4Nb1.5 (at%) is an alloy designed for metallic glass formation, and the critical cooling rate is estimated to 2500 K/s [9]. There is a potential risk for crystallisation in the heat affected zone (HAZ) in the material produced by PBF-LB—mainly because of reheating from adjacent laser scans and subsequent layers [11,12]

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Conclusion