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SULI Deliverables Using: Python-B1500 [Slides]

A new electrical setup for testing ECRAM devices is described in this presentation. This presentation details the background of ECRAM devices, how the B1500 is used to program ECRAM devices, and the python GUI that was created for controlling the B1500. ECRAM devices are a form of non-volatile memory. The stored data is the resistance between two of the terminals on the device. Using only the B1500, the ECRAM devices can be programmed and the state read out. This creates a simple, logical testing setup. The overall setup was successful, ECRAM devices could easily be programmed and measured. However, there is still room for improvement. Specifically, in the creation of an automated “Program” feature and a “Data Collection” feature. These features will require additional advances in the understanding of ECRAM devices but will greatly automate and improve the current data collection and application of ECRAM devices.

42 ENGINEERING

Validation of a Custom Ball-on-Ring Apparatus and Consideration of Common Issues for Use in Further Testing (SULI Deliverables)

Ceramic materials are well-known for their high hardness and strength but are limited in their application due to low toughness and sudden failure. As a potential solution, inspiration can be taken from dental enamel nanostructure, where undulating rods cause cracks to branch or deflect, increasing the energy needed to cause total fracture of a ceramic part. Following the dental enamel structure, a novel ceramic which uses 3D printed Yttria stabilized Zirconia rods in an alumina matrix was developed. To test this bio-inspired ceramic material, a proper testing apparatus needed to be created and tested to verify its accuracy. For this project, a bespoke ball on ring testing apparatus was created and tested using both conventionally sintered alumina disks and purchased alumina disks to validate its accuracy. By comparing the Weibull distribution of rupture strengths measured by the tests to literature values, it was shown that the testing frame had a wide distribution of strength which did not align with literature values on the lower end. Through fractography, it was found that some samples fractured from the contact stress induced by the ball indenter, which could not be used to calculate rupture strength. This fracture was often linked to low stress to failure, which was initiated by a flaw on the surface near the indenter which acted as a stress concentrator. Removal of these samples from the data set increased the accuracy of the reported rupture strength values for the ceramic. Considering the equations for the magnitude of contact and flexural strength, along with observations of initiating flaws, several measures can be taken for testing the bio-inspired composite. These measures include proper polishing of both sides of the sample, reducing sample thickness, and potentially using a softer indenter material.

36 - MATERIALS SCIENCE

Data Analysis, Machine Learning, & More

At LANL, I have had the privilege and pleasure of working with Dr. Tika Kafle, an optics and condensed matter physicist at the MagLab in TA-35. Dr. Kafle’s research primarily involves the Angle Resolved Photoemission Spectroscopy (ARPES) technique of characterizing materials. More specifically, Dr. Kafle works with Time Resolved ARPES (Tr-ARPES), which extends this technique into the time domain.

36 MATERIALS SCIENCE