Yl. Chen et Ar. Jones, Reduction of porosity in oxide dispersion-strengthened alloys produced by powder metallurgy, MET MAT T A, 32(8), 2001, pp. 2077-2085
In this work, the porosity in a iron-based oxide dispersion-strengthened (O
DS) alloy, namely, PM2000, has been studied together with its recrystalliza
tion behavior. It has been found that pores are only found in coarse second
ary recrystallized grains formed at the early stage of recrystallization. I
t is suggested that a lack of fast diffusion paths, particularly grain boun
daries, will prevent gas trapped in the materials during mechanical alloyin
g (MA) from diffusing away, and porosity is formed as a result. Thus, it is
proposed that an extended anneal below the secondary recrystallization tem
perature will help to reduce the subsequent evolution of porosity in these
materials, and the method has been demonstrated to work successfully in PM2
000.