  High-throughput experiments that use combinatorial samples with rapid
measurements can be used to provide process-structure-property information at
reduced time, cost, and effort. Developing these tools and methods is essential
in additive manufacturing where new process-structure-property information is
required on a frequent basis as advances are made in feedstock materials,
additive machines, and post-processing. Here we demonstrate the design and use
of combinatorial samples produced on a commercial laser powder bed fusion
system to study 60 distinct process conditions of nickel superalloy 625: five
laser powers and four laser scan speeds in three different conditions.
Combinatorial samples were characterized using optical and electron microscopy,
x-ray diffraction, and indentation to estimate the porosity, grain size,
crystallographic texture, secondary phase precipitation, and hardness.
Indentation and porosity results were compared against a regular sample. The
smaller-sized regions (3 mm x 4 mm) in the combinatorial sample have a lower
hardness compared to a larger regular sample (20 mm x 20 mm) with similar
porosity (< 0.03 %). Despite this difference, meaningful trends were identified
with the combinatorial sample for grain size, crystallographic texture, and
porosity versus laser power and scan speed as well as trends with hardness
versus stress-relief condition.
