Image icon  Al 96, Cu 4 (wt%), solution treated and overaged - precipitation hardening

Use this resource: Use this resource icon
Link to this page:
View at:            
Resource type: Image
Description: This sample has been aged after quenching to enable the growth of precipitates from a supersaturated solid solution. The strength of the alloy has been greatly improved by precipitation hardening. A precipitation sequence is observed eventually resulting in the formation of the stable θ phase through a series of metastable intermediates. The θ phase is an intermetallic compound with a composition close to CuAl2. The θ precipitates preferentially form on Al grain boundaries, as these are excellent heterogeneous nucleation sites. The depletion of Cu near the boundaries to these precipitates is one reason for the formation of adjacent precipitation free zones (PFZ).
Keywords: alloy • aluminium • copper • metal • metastable • overaged • precipitation • precipitation hardening • quenching • solution heat treatment
Categories: Science approaches > Microstructure
Science approaches > Strengthening mechanisms > Precipitation (age) hardening
Materials > Metals & alloys > Aluminium & alloys
Processes > Thermal treatments > Quenching
Processes > Thermal treatments > Ageing
Testing, analysis & experimentation > Metallography
Scale > Micro
Created by: DoITPoMS, University of Cambridge
Prof T W Clyne, Department of Materials Science and Metallurgy, University of Cambridge
Published by: DoITPoMS, University of Cambridge
License: This resource is released under the Creative Commons Attribution Non-Commercial Share Alike license (2.0 UK: England & Wales).
Creative Commons Attribution Non-Commercial Share Alike logo
You are free:
  • to share – to copy, distribute and transmit the work
  • to remix – to adapt the work
Under the following conditions:
  • attribution – You must attribute the work in the manner specified by the author or licensor (but not in any way that suggests that they endorse you or your use of the work).
  • noncommercial – You may not use this work for commercial purposes.
  • share alike – If you alter, transform, or build upon this work, you may distribute the resulting work only under the same or similar license to this one.
View the full legal code here.
Date created: 25 October 2001
Date added: 21 August 2009
Resource ID: 1122