权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Research on Nucleation Site of Martensitic Transformation by High Magnetic Field Application

强磁场马氏体相变形核位点研究

基本信息

批准号：
07455256
负责人：
SHIBATA Koji
金额：
$ 3.97万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07455256/
关键词：
stainless steel alpha' martensite cooling rate pre-strain re-heating thermal stress thermal strain number of nucleation site マルテンサイト変態核生成サイト強磁場鉄鋼

项目摘要

Effects of cooling rate from solution treatment temperature, pre-strain before sub-zero cooling and reheating before sub-zero cooling on formation of alpha'martensite in SUS 304L steel with and without an application of high magnetic fields were examined. Rapid cooling from solution treatment temperature increases the formation of alpha'martensite. Small pre-strain at room temperature is attributable to a formation of epsilon martensite at the sub-zero temperature. Pre-strains over around 1% decrease the amount of alpha'martensite and 3% pre-strain depresses the formation almost completely. Application of high magnetic fields up to 26 tesla can enhances the formation of alpha'martensite in the steel pre-strained by over 3%. It is conseived from the compairing the magnetic driving energy and depression energy by work-hardening that this depression cannot attributes to the suppression of the growth of nuclei of martensite due to work-hardening but to the reduction of the number of the nucleation site. Re-heating at around 500ﾟC before cooling suppresses the formation of the martensite. This phenomena occurs through time dependent process showing activation energy of diffusion of substitutional elements. This depression is attributable to break-down of the nucleation sites induced by quenching from solution treatment temperature. Water quenching from re-heating temperatures over 500ﾟC increases the amount of alpha' martensite but air cooling from those temperatures does not increase. From these results, it was thought that quenching from solution treatment and re-heating temperatures over 500ﾟC induces strains through thermal stress in the specimens and such strains play an important role as nucleation sites.

研究了在施加和不施加强磁场的情况下，固溶温度冷却速度、低温前预应变和低温前再加热对sus304l钢α′马氏体形成的影响。固溶处理温度的快速冷却增加了α马氏体的形成。室温下预应变小是由于在零下温度下形成了ε马氏体。超过1%的预应变使α马氏体数量减少，3%的预应变几乎完全抑制了α马氏体的形成。施加高达26特斯拉的强磁场可使预应变钢中α马氏体的形成提高3%以上。通过比较加工硬化的磁驱动能和抑制能可以看出，这种抑制不是由于加工硬化抑制了马氏体核的生长，而是由于成核位点数量的减少。冷却前在500℃左右再加热可抑制马氏体的形成。这种现象是通过时间依赖过程发生的，显示了取代元素扩散的活化能。这种下降是由于固溶处理温度淬火引起的成核部位的破坏。再加热温度超过500℃的水淬火会增加α′马氏体的数量，但在此温度下空气冷却不会增加α′马氏体的数量。综上所述，固溶淬火和500℃以上的再加热温度可通过热应力诱发应变，这些应变作为晶核位点起着重要作用。