Control of Interphase Bowdlerizes in Steel

（α+γ）和（α+θ）片层组织经冷轧和退火后形成α晶粒尺寸小于1 μm的微双相组织。（α+γ）相为亚晶结构，（α+θ）相为大角度和小角度晶界，γ相VC和α相s-Cu经固溶时效后均与基体共格。但在基体再结晶后，它们失去了原有的取向关系，变得不相干。在Ni-Cr合金中，从面心立方（fcc）基体中析出的bcc相，无论是否存在近合理的取向关系，析出相（bcc）/基体（fcc）界面都呈现出平面的小平面，其中通常含有台阶和规则排列的线缺陷。通过对几何近重合位模型的分析，确定了超高碳钢中平面小面的边界取向对应于相干原子密度较高的平面，研究了超高碳钢（α+θ）组织与超塑性行为的关系。珠光体组织经奥氏体化、淬火和回火处理后，形成具有大角度α晶界的（α+θ）微复相组织。在973 K的拉伸试验中，奥氏体化、淬火和回火的试样比温轧态试样显示出大得多的超塑性延伸率。在奥氏体中MnS+V（C，N）复合沉淀物的晶内铁素体自形核过程中，铁素体与奥氏体基体之间没有特定的取向关系，表明铁素体相变织构是随机的。

The (α+γ) and (α+θ) lamellar structures are heavily cold rolled and annealed to form the microduplex structures of which α grain size is less than 1 μm. α phase exhibits a subgrain structure in the (α+γ) case whereas α phase contains both of high angle and low angle boundaries in the (α+θ) case.VC in y.and s-Cu in α are both coherent to their matrices after solution treatment and aging. However, they become incoherent by losing the original orientation relationship after the recrystallization of matrix. After losing coherency, these precipitates coarsens vary rapidly.In the bcc precipitation from fcc matrix in a Ni-Cr alloy, regardless of the presence of near rational orientation relationship, precipitate (bcc)/matrix(fcc) interphase boundaries exhibit planar facets that often contain ledges and regularly aligned line defects. The boundary orientations of the planar facets correspond to the planes with the higher densities of coherent atoms by analyzing the geometrical near coincidence site model.Relation between the (α+θ) microstructure and the superplastic behavior in ultra-high carbon steels has been studied. The austenitizing, quenching and tempering treatment of pearlite structure produces an (α+θ) microduplex structure with high angle α grain boundaries. The specimen austenitized, quenched and tempered shows much larger superplastic elongation in the tensile tests at 973K than the as warm rolled specimens. This structure also exhibits the superior strength-ductility balance at room temperature.In the nucleation of intragranular ferrite idiomorphs on the incoherent MnS+V(C, N) complex precipitates in austenite, there is no specific orientation relationship between the ferrite and its austenite matrix indicating that the ferrite transformation texture could be randomized.