Microstructure and Strength Properties of Unidirectionally Solidified Cobalt-Niobium Eutectic Alloy,

Abstract

The room temperature mechanical properties of unidirectionally solidified Co-Co3Nb eutectic alloy have been studied. Solidification rates varying from 0.000128 cm/sec to 0.001764 cm/sec were employed in producing various microstructures. A well defined lamellar microstructure is produced at rates below 0.000317 cm/sec, while above this rate a lamellar-dendritic structure exists. Room temperature compression and hardness tests indicated increased strengthening with increasing solidification rate as well as verification of a Hall-Petch dependence of fracture stress and hardness upon interphase spacing. Brittle fracture in both types of structure was seen to be initiated by slip in the ductile Co3Nb phase and promoted by crack propagation in the brittle alpha-cobalt solid solution phase. (Author)

Document Details

Document Type
Technical Report
Publication Date
Nov 01, 1971
Accession Number
AD0733677

Entities

People

  • John P. Gudas

Tags

DTIC Thesaurus Topics

  • Alloys
  • Compression
  • Crack Propagation
  • Cracks
  • Dendritic Structure
  • Hardness
  • Mechanical Properties
  • Microstructure
  • Physical Properties
  • Solid Solutions
  • Solidification
  • Transition Temperature
  • Verification

Fields of Study

  • Materials science

Readers

  • Materials Science (Mechanical Engineering).
  • Powder metallurgy of Titanium alloys.

Technology Areas

  • Space
  • Space - Hall-Effect Thruster