An Investigation of the Structure and Properties of Aged Aluminium Bronzes

Abstract

The ageing response of wrought single phase aluminium bronze alloys
containing additions of cobalt up to 1% is assessed for use as a
bolting material by mechanical tests, microstructural examination, and
constant strain rate stress corrosion trials. The dependence of
mechanical properties on cobalt concentration, degree of ageing and
level of cold work is established. The presence of a precipitation
hardening mechanism is identified. The hardening phase in the final
stages of the precipitation sequence is shown to be a compound based
on CoAl having an orientation with respect to the matrix of [101] m||
[lil] ppt, (111) m || (110) ppt. A susceptibility to stress corrosion
cracking is established for the alloy system. Two basic mechanisms
are identified 1) A strain-generated active path mechanism for
solutions of pH=12 and 2) a pre-existing active path mechanism for a
sea water environment. The susceptibility to stress corrosion cracking
in seawater is shown to depend on the metallurgical condition of the
alloy.

Date of Award	1979
Original language	English
Awarding Institution	Aston University