Microstructure and plastic deformation in (C11_b/C40) duplex-phase silicide with a sigle set of lamellae

研究了由NbSi2、VSi2或TiSi2与MoSi2组合而成的C40/C11b双相硅化物的微观结构，重点研究了片层的形成和取向。在NbSi2/MoSi2双晶中，NbSi2/MoSi2双晶通过区域熔化和适当的热处理形成了片层结构，但只有NbSi2/MoSi2双晶获得了取向的片层结构。定向层状结构满足(0001)_&lt；C40&gt；//(110)_&lt；C11b&gt；，&lt；1^-21^-0]_&lt；C40&gt；//[11^-0]_&lt；C11b&gt；和&lt；101^-0]_&lt；C40&gt；//[001]_&lt；C11b&gt；形成了C11b相的三种变体和两种晶界：一种C11b/C11b晶界和一种C11b/C40相界。此外，由于晶界失配应变的松弛，进一步的退火导致了两相的粗化，改变了晶界的结晶关系。

Microstructures of duplex-phase C40/C11_b silicides from combinations of NbSi_2, Vsi_2 or TiSi_2 with MoSi_2 were investigated focusing on formation and alignment of lamellae. The lamellar structure was formed by zone melting and subsequent appropriate heat treatment for all combinations, but oriented lamellae were obtained only in NbSi_2 / MoSi_2 duplex crystals. The oriented lamellar structure satisfied the crystallographic relationship of (0001) _<C40> // (110) _<C11b>, < 1^^-21^^-0] _<C40> // [11^^-0] _<C11b> and < 101^^-0] _<C40> // [001] _<C11b>, resulting in formation of three variants of the C11_b phase and two kinds of boundary: a type of C11_b/C11_b grain boundary and a type of C11_b/C40 phase boundary. Further annealing induced coarsening of both phases and changed the crystallographic relation due to relaxation of misfit strain at boundaries.