A microscale additive manufacturing approach for in situ nanomechanics

Abstract

In situ nanomechanics in scanning electron microscope (SEM) and transmission electron microscope (TEM) has been the gold-standard for direct observation of deformation mechanisms of metals and alloys. The extracted deformation mechanisms complement the process – microstructure – property relationship that is required for the full understanding of the mechanical behavior of these materials. Micro-pillar compression is perhaps the most frequently used method for such studies. Fabrication of micro-pillars from bulk materials relies on milling by the focused ion beam (FIB), which often requires several tens of hours of the equipment time, and the associated expenses. Additionally, the heavy ion bombardment by FIB may introduce damage into materials, which in turn may result in compromised interpretation of materials’ behavior. We introduce a microscale additive manufacturing (AM) approach that enables direct deposition of nano-pillars and micro-pillars of metals and alloys in room environment. In addition to the size, this process allows control over the microstructure of the deposited metals and alloys. Depending on the size and microstructure, a typical micro-pillar can be fabricated in a few minutes to tens of minutes at very low cost and without any beam-induced damages. When combined with in situ instrumentation, this approach may enable high-throughput investigation of the process – microstructure – property relationship, in particular for nano-crystalline and nano-twinned metals and alloys.