Development of a Microcircuit Grid Technique for Automated Crack Length Measurement for Fatigue Testing at Elevated Temperature

Abstract

A microcircuit grid technique was investigated and used to measure crack lengths in fatigue crack growth test specimens of an aluminum alloy (7075- T6) at room temperature and a nickel-based superalloy (Inconel 718) at 650 C as part of a Phase I SBIR program supported by the Air Force. Crack lengths were determined from stepwise changes in the resistance of microcircuit grids deposited on compact tension specimens by a photolithography process. Crack lengths assessed from discrete voltage changes recorded for a grid on a bridge circuit agreed closely with direct optical measurements. The fatigue crack growth data obtained from both alloys were in agreement with the data in the literature. Keywords: Microcircuit grids, Automated fatigue testing, High temperature test capability, Spectrum loading.

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Document Details

Document Type
Technical Report
Publication Date
May 01, 1988
Accession Number
ADA198003

Entities

People

  • Anil V. Virkar
  • Dinesh K. Shetty
  • Kevin Stuffle
  • Raymond A. Cutler

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Acquisition
  • Air Force
  • Aluminum Alloys
  • Ceramic Materials
  • Classification
  • Commerce
  • Crack Tips
  • Data Acquisition
  • Fatigue Tests (Mechanics)
  • High Temperature
  • Lead Wires
  • Materials
  • Materials Science
  • Measurement
  • Monitoring
  • Resistance
  • Security

Readers

  • Fluid Mechanics and Fluid Dynamics.
  • Integrated Circuit Design and Technology.
  • Materials Science (Mechanical Engineering).

Technology Areas

  • Microelectronics