In-Situ Micro-Mechanical System for Testing of Advanced Materials Under Extreme Conditions of Temperature, Strain-Rate and Applied Stress

Abstract

Major Goals: This DURIP grant provided support for expanding the capabilities of the Alemnis in-situ micromechanical system to include extreme conditions of temperature (-150 to 1000 C), a wide range of applied strain rates (10^-4 to 10^4/s) and high applied stresses. In the current materials and mechanical research environment, mechanical properties of microscale volume are traditionally studied using indentation tests which are conducted at quasistatic rates (i.e. strain rates in the range of 10^-5 to 10^-2 /s) and under ambient conditions (s room temperature). However, the dynamic properties of the local regions of interest remain unexplored, especially at elevated/cryogenic temperatures and applied stresses. With the newly expanding capabilities of our current Alemnis in-situ SEM system we have been able to evaluate the local material response over wide extremes of temperature, strain rates and loading conditions. The DURIP award provided a number of upgrades to our existing Alemnis Standard Assembly (ASA) manufactured by Alemnis AG in order to enhance its capabilities for testing under extreme conditions. Micro-mechanical tests are moving beyond the basic measurement of hardness and elastic modulus to encompass a host of different mechanical properties such as strain rate sensitivity, stress relaxation, creep, and fracture toughness by taking advantage of focused ion beam (FIB) milled sample geometries (e.g., micropillars, micro-tensile geometries, beams, etc.) and additively manufactured (AM) microstructures. New developments, such as high strain rate and high and low-temperature tests, are needed to extend the range of properties that can be studied at the micro and nanoscale. However, such techniques are challenging due to low oscillation frequencies, long duration of tests, and significant thermal drift when attempted with standard indentation instruments. Therefore such capabilities are scarce within the US as well as internationally.

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Document Details

Document Type
Technical Report
Publication Date
Apr 30, 2022
Accession Number
AD1193190

Entities

People

  • Siddhartha Pathak

Organizations

  • Iowa State University

Tags

Communities of Interest

  • Advanced Electronics
  • Space
  • Weapons Technologies

DTIC Thesaurus Topics

  • Advanced Materials
  • Composite Materials
  • Crack Propagation
  • Crystal Structure
  • Electron Microscopes
  • Electron Microscopy
  • Fabrication
  • Material Degradation Processes
  • Materials
  • Materials Laboratories
  • Materials Processing
  • Materials Science
  • Materials Testing
  • Mechanical Properties
  • Mechanical Working
  • Mechanics
  • Microscopes
  • Nanocomposites
  • Phase Transformations
  • Physical Vapor Deposition
  • Scanning Electron Microscopes
  • Three Dimensional
  • Transition Temperature

Readers

  • Mechanical Engineering/Mechanics of Materials.
  • Nanoscale Plasmonic Nanotechnology
  • Systems Analysis and Design