号数	ばね論文集 64 号（ 2019 年）
ページ数	pp.9-14
種類	論文
論文名	圧延と焼なましがFe-Mn-Si 形状記憶合金の形状記憶特性に及ぼす影響
Title	Effect on Mechanical Properties of Fe-Mn-Si Shape Memory Alloy by Rolling and Annealing
著者	江原大貴1), 納冨充雄2)
Author	Hirotaka EHARA1), Mitsuo NOTOMI2)
抄録	Fe-Mn-Si系合金の形状記憶効果（SME）は，γ ⇄ εマルテンサイト変態に関連する．SMEを改善するためには，すべり変形を抑制し，マルテンサイト変態を優先的に生じさせる必要がある．この研究では，各試験片を圧延および焼なましを施した後，それらの弾性回復率および形状回復率を曲げ試験により定量した．また，相分布図を得るために電子後方散乱回折（EBSD）によって結晶構造を調べ、次いで極点図を作成した。圧下率20%及び40%の試験片において結晶の配向は[001], [2√2 0 1 ], [(√2) √6 1], [(√2 √6 1]または[001], [(2√2 0 1 ], [√2 √6 1], [√2 √6 1]であった．圧下率（RR）20%では弾性回復率が27%から36%に改善され，RR40%では40%まで改善した．また，形状回復率は改善しなかった．600℃の焼なまし後，形状回復率はRR40%の試料で20%から33%に改善した．冷間圧延により，降伏応力上昇するとともに曲げ試験によるマルテンサイト相が増大し，擬弾性効果を高めたことが弾性回復率の増加を誘導した．一方，SMEを改善する2つの理由があり，マルテンサイト変態を増加させる集合組織の形成と，マルテンサイト相に容易に変態するオーステナイト相の生成である．
Abstract	The shape memory effect (SME) in Fe-Mn-Si based alloy is associated withγ⇄εmartensitic transformation. It is necessary to suppress the sliding deformation and promote preferential generation of the martensitic transformation in order to improve the SME. In this study, each specimen was rolled and/or annealed and then the elastic and shape recovery ratios of them were checked by means of the bending mechanical test. Crystal structures also were inspected by electron backscatter diffraction (EBSD) for obtaining the phase distribution maps and then pole figures were drawn. On the specimens rolled as 20% and 40% reduction rate the axis of some crystals oriented to one of [001], [2√2 0 1 ], [(√2) √6 1], [(√2 √6 1] and the other of [001],[(2√2 0 1 ], [√2 √6 1], [√2 √6 1]. The elastic recovery ratio improved from 27% to 36% at the reduction ratio（ RR）at 20% , and to 40% at the RR 40% , however the shape recovery ratio was not improved. After the 600℃ annealing the shape recovery ratio improved from 20% to 33% in the RR 40% specimens. The cause of the elastic recovery ratio improvement is presumed that the cold rolling raised yield stress, and the expansion of martensite phase after bending test enhanced pseudoelastic effect. On the other hand, there are two reasons for improving the SME, one is the texture formation which promotes the martensitic transformation, and the other is the generation of austenite phase which easily transforms into martensite phase.
著者の所属	1）明治大学大学院 2）明治大学
Belonging	1）Meiji University Graduate School 2）Meiji University
Key Words	Fe-Mn-Si alloy, Elastic recovery ratio, Shape recovery ratio, EBSD, Cold rolling, Annealing