相变研究的重要性——以Spinodal分解示例

Significance of phase transformation studies——taking spinodal decomposition as an example

以Spinodal分解为例,说明相变研究的重要意义。铁素体不锈钢中呈现400-550℃时效脆性的原由为Spinodal分解而非有序化。介绍了含不溶区间及Spinodal线的Fe-Cr相图。Mn-Al-C钢奥氏体经Spinodal分解显示抗拉强度和屈服强度分别增至1120 MPa和1080 MPa,伸长率约30%,值得给予关注。Cu-15Ni-8Sn和Cu-15Ni-8Sn-0.2Nb合金由于Spinodal分解和有序析出相呈显著强化,并具良好应力松弛,高的弹性模量和导电性。Cu-Ni-Sn经Spinodal分解还会出现胞状或条状组织,称非连续Spi-nodal分解,铝合金时效时也会发生Spinodal分解,Co45Cu55薄膜通过Spinodal分解显示18%的最大巨磁阻。

This paper illustrates the significance of phase transformation studies taking the spinodal decomposition as an example.The 400-550 ℃ aging embrittlement in ferritic stainless steels is attributed to the spinodal decomposition rather than the ordering,and Fe-Cr phase diagrams with miscibility gap and spidonal line are introduced.It is worthy to be noticed that the ultimate tensile strength and yield strength of Mn-Al-C steel can be increased to 1120 MPa and 1080 MPa,respectively,with elongation of 30% by spinodal decomposition of austenite.Cu-15Ni-8Sn and Cu-15Ni-8Sn-0.2Nb alloys exhibit remarkable strength,good stress release ability and high elastic modulus as well as considerable electrical conductivity after subjecting spinodal decomposition and ordered phase precipitation.In Cu-Ni-Sn system,there may appear cellular or lamellar microstructure after spinodal decomposition and it is termed as discontinuous spinodal.In aging process of aluminum alloy,there may occur the spinodal decomposition.The maximum giant magnetoresistance was found to be 18% for a Co（45）Cu（55） thin film alloy through spinodal decomposition.