Lehigh University

Mri: Acquisition of a Plasma Focused Ion Beam System for Dynamic In-situ Micro-mechanical Testing Over Cryogenic and Elevated Temperatures -direct Observation of Deformation Behavior at the Micro/nano Scales Can Lead to Significant Advances in Our Understanding of the Deformation Mechanisms in Materials by Correlating Microstructural Changes With Load-displacement Characteristics. for Example, the Propagation of a Crack-tip That Would Lead to a Catastrophic Failure of a Component, or Deformation/temperature-induced Phase Transformations and Crystallinity Changes Are Important Processing Phenomena That Can Lead to Failure in Materials. the Plasma Focused Ion Beam (FIB) in This Project Allows Researchers to Efficiently Extract Samples From Specific Sites of Interest in Materials for Micromechanical Testing, Which Can Be Performed Using a State-of-the-art Micromechanical Testing Device Integrated Within the Same Fib Instrument. It Is Possible to Observe Both Microstructural and Crystallographic Changes That Occur During Deformation Using This System, and These Changes Can Be Directly Correlated With Localized Stress-strain Data. the Equipment Will Benefit a Wide Variety of Funded Research Activities at Lehigh Across Sectors of Materials Science Ranging From Ceramics, Metals/alloys, 3D-PRINTED Materials, Polymers and Biomaterials. in Addition, the Rapid Material Removal Rate Achievable in the Plasma Fib Accelerates the Fabrication of a Wide Range of Nanostructures Such as Tooling for Micro/nano Injection Molding, as Well as Enable Large-scale Internal Characterization of Various Samples Including Highly Sensitive Biomaterials and Soft Polymers at Cryogenic Temperatures. the Instrument Also Supports Research Projects From Other Universities, Government Labs and Industry Through Liaison Programs Already Established at Lehigh. the Techniques and Knowledge Developed Using This System Are Shared With Lehigh Students as Well as Numerous Industry/government Attendees of the Lehigh Microscopy Schools. the System as Specified Consists of (1) a Plasma Focused Ion Beam (FIB) Instrument, Integrated With (2) a State-of-the-art In-situ Micromechanical Testing Device With Testing Capability Over a Wide Temperature Range and (3) a High Speed Electron Backscattered Diffraction (EBSD) Camera. the System Will Be Able to Simultaneously Acquire Many Types of Data, Including Highly Sensitive Transmission Kikuchi Diffraction Patterns, During Mechanical Testing. the Rapid Milling Rate of the Xe-ion Based Plasma Fib, Which Is ~10?100 Times Greater Than Conventional Ga-ion Systems, Markedly Increases the Fabrication Throughput of Micromechanical Test Samples, and Hence Addresses What Is Currently a Severe Limitation, Namely the Ability to Test a Statistically Significant Number of Samples. In-situ Mechanical Testing Within the Fib at Temperatures From Minus 130 to 1000 Degrees C Will Enable the Correlation of Deformation Processes (such as Slip and Microcrack/void Nucleation) With Microstructural Features at the NM Scale. Furthermore, the Load-displacement Signals Can Be Sampled at 1.2 MHZ, Which Is Much Faster Than the Typical Frame Rates Encountered in Sem Imaging. This Information Will Be Complemented by Digital Image Correlation, Which Will Be Used to Quantify Localized Deformation. These Capabilities Are Highly Advantageous, But What Makes the Requested Instrumentation Truly Unique Is the Ability to Simultaneously Extract Real Time Ebsd Data During Mechanical Testing, Which Is Made Possible by a Novel Test Platform Geometry. Moreover, the Efficiency of Serial Cross-sectioning for the Characterization of Multi-component Materials, as Well as Specific Features Such as Interfaces and Boundaries in Materials and Devices, Is Improved Tremendously. the Sample Sectioning Capability at Cryogenic Temperatures Is Especially Useful for Cross-sectional Observation of Soft Materials Such as Polymers and Biological Samples, and for Thin-specimen Preparation to Allow More Detailed Observation in a Transmission Electron Microscope. This Award Reflects NSF'S Statutory Mission and Has Been Deemed Worthy of Support Through Evaluation Using the Foundation's Intellectual Merit and Broader Impacts Review Criteria.