The quantitative evaluation of effect of strain gradient on the strengthening and structure refinement of metals during ultra large straining

超大应变过程中应变梯度对金属强化和组织细化作用的定量评价

• 批准号: 18360329
• 负责人: UMEMOTO Minoru
• 金额: $ 10.21万
• 依托单位: Toyohashi University of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2006
• 资助国家: 日本
• 起止时间: 2006 至 2007
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-18360329/
• 关键词: ultra large strain; strain gradient; strengthening; grain refinement; high pressure torsion; crystallization; pressure induced transformation; GN dislocation; 材料; ひずみ; 強度; 組織; ひずみ勾配

In the present investigation, using specimens with different strain and strain gradient prepared by high pressure torsion machine, the effect of strain gradient on the strengthening and refinement of microstructure were studied. The measurement of hardness for HPTed pure metals such as Al, Ti, Ni, Cu, Fe revealed that recrystallization takes place in the pure metals with low melting point such as Al and Cu. Pressure induced transformation was observed in pure Ti. Thus using pure Fe in which only the effect of strain and strain gradient appears, the effect of strain and strain gradient on the hardness was studied. The clear strain gradient hardening was observed in the HPTed pure Fe. The HPTed Fe showed the ultimate tensile strength of 2GPa, and the total elongation increased with applied strain. The effect of high pressure during HPT was examined using pure Ti which transformed from phase to w phase when HPTed at high pressure. The volume fraction of CO phase increases with strain and with decreasing oxygen content. The co phase is metastable at ambient conditions and it transforms back to a phase during heating.

采用高压扭转机制备了不同应变和应变梯度的试件，研究了应变梯度对组织强化和细化的影响。对Al、Ti、Ni、Cu、Fe等高熔点纯金属的硬度测试表明，低熔点纯金属Al、Cu发生再结晶。在纯钛中观察到了压力诱导相变。在纯铁中只存在应变和应变梯度的情况下，研究了应变和应变梯度对硬度的影响。在高温高压处理的纯铁中观察到明显的应变梯度硬化。HPTed Fe的极限抗拉强度为2 Gpa，总延伸率随施加应变的增加而增加。以纯钛为研究对象，考察了高压下高温合成过程中高压的影响。CO相的体积分数随应变和含氧量的降低而增加。Co相在环境条件下是亚稳定的，在加热过程中它会转变回一个相。

项目成果

Formation of ultrafin grained structure in SUS 304 stainless steel produced by high pressure torsion(HPT).

高压扭转 (HPT) 法在 SUS 304 不锈钢中形成超细晶粒结构。

• 发表时间: 2007
• 期刊: Materials Science Forum 561-565
• 作者: J. G. Li;M. Umemoto;Y. Todaka and K. Tsuchiya
• 通讯作者: Y. Todaka and K. Tsuchiya

Tensile property of ultrafine grained ferritic steel produced by HPT strafining.

HPT 钢厂超细晶铁素体钢的拉伸性能

• 发表时间: 2007
• 作者: J.G.Li;M.Umemoto;Y.Todaka;K.Tsuchiya;好井美樹;好井 美樹;永井宏典;本敬行;熊谷匡明;戸高義一;戸高義一;戸高 義一;戸高 義一;戸高義一;永井宏典;熊谷匡明;戸高 義一
• 通讯作者: 戸高 義一

HPT 加工とその後の加熱による純 Ti の組織と力学特性の変化

HPT 加工和后续加热导致纯钛的结构和机械性能发生变化

• 发表时间: 2007
• 作者: Kakae N.;Tsuchihashi T.;Tanaka Y.;Ohmiya Y.;Harada K.;佐々木 洵
• 通讯作者: 佐々木 洵

Formation of surface nanocrystalline structure in steels by shot peening and role of strain gradient on grain refinement by deformation

喷丸处理钢表面纳米晶结构的形成以及应变梯度对变形细化晶粒的作用

• 发表时间: 2007
• 期刊: ISIJ International Vol.47
• 作者: Y. Todaka;M. Umemoto;Y. Watanabe;A. Yamazaki;C. Wang and K. Tsuchiya
• 通讯作者: C. Wang and K. Tsuchiya

A microstructural investigation of the surface of a drilled hole in carbon steels

• DOI: 10.1016/j.actamat.2006.09.043
• 发表时间: 2007-02-01
• 期刊: ACTA MATERIALIA
• 影响因子: 9.4
• 作者: Li, J. G.;Umemoto, M.;Tsuchiya, K.
• 通讯作者: Tsuchiya, K.