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Effect of Cl on microstructure and mechanical properties of in situ Ti/TiB MMCs produced by a blended elemental powder metallurgy method
Author(s) -
FAN Z.,
NIU H. J.,
CANTOR B.,
MIODOWNIK A. P.,
SAITO T.
Publication year - 1997
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1046/j.1365-2818.1997.d01-622.x
Subject(s) - materials science , microstructure , metallurgy , ductility (earth science) , powder metallurgy , alloy , ultimate tensile strength , grain size , lath , titanium , grain boundary , refining (metallurgy) , martensite , creep
A modified blended elemental powder metallurgy (MBEPM) method has been developed for the production of low‐cost Ti alloys and in situ Ti/TiB MMCs for automobile components such as connecting rods and inlet and exhaust valves. The MBEPM method uses Ti sponge fines as raw material, which contain a substantial amount of Cl. The Cl refines the microstructure of the as‐sintered Ti–6Al–4V alloys, with a reduced prior β‐grain size and a reduced α‐lath size and aspect ratio. However, the grain refining effect of Cl is much less pronounced in as‐sintered Ti–6Al–4V–10%TiB MMCs. The Cl is present in the as‐sintered microstructure in three forms: (1) shells consisting of fine NaCl particles in macropores; (2) cuboidal NaCl precipitates in the alloy matrix; and (3) Cl and Na segregated to prior β‐grain boundaries. Increasing the Cl content increases the tensile ductility of both Ti–6Al–4V alloys and Ti–6Al–4V–10%TiB MMCs, but has little effect on strength.