Ti-(45-X)Ni-5Cu-X(Mo,Cr,Al)(at.%) 합금의 B2-B19-B19` 변태거동 및 형상기억특성

李喜佑,崔美善,金載勳,南泰鉉 대한금속재료학회 2002 대한금속·재료학회지 Vol.40 No.6

Transformation behavior and shape memory characteristics in Ti-(45-X)Ni-5Cu-X(Mo, Cr, Al)(at.%) alloys were investigated by means of differential scanning calorimetry, X-ray diffraction and thermal cycling tests under a constant load. The substitution of Mo, Cr and Al for Ni in Ti-45Ni-5Cu alloy induced the B2→B19 martensitic transformation prior to the B2→B19' transformation, and consequently Ti-(45-X)Ni-5Cu-X(Mo, Cr, Al)(at.%) alloys transformed in two stages; the B2→B19→B19'. The B2→B19 and the B19→B19' transformations were completely separated in Ti-(45-X)Ni-5Cu-X(Mo, Cr) alloys, whereas they were not done in a Ti-44.3Ni-5Cu-0.7A1 alloy without applied stress. The substitution of Mo, Cr and Al in a Ti-45Ni-5Cu alloy decreased transformation hysteresis and the residual elongation. The maximum recoverable elongation of Ti-(45-X)Ni-5Cu-X(Mo, Cr, Al) alloys was about 5%.

Cu(B)/Ti/SiO₂ 구조를 열처리할 때 일어나는 미세구조 변화에 미치는 Ti 하지층 영향

이재갑,Lee Jaegab 한국재료학회 2004 한국재료학회지 Vol.14 No.12

Annealing of $Cu(B)/Ti/SiO_2$ in vacuum has been carried out to investigate the effects of Ti underlayer on microstructure in $Cu(B)/Ti/SiO_2$ structures. For comparison, $Cu(B)/Ti/SiO_2$ structures was also annealed in vacuum. Three different temperature dependence of Cu growth can be seen in $Cu(B)/Ti/SiO_2$; B precipitates- pinned grain growth, abnormal grain growth, normal grain growth. The Ti underlayer having a strong affinity for B atoms reacts with the out-diffused B to the Ti surface and forms titanium boride at the Cu-Ti interface. The formation of titanium boride acts as a sink for the out-diffusion of B atoms. The depletion of boron in grain boundaries of Cu films, as results of the rapid diffusion of B along the grain boundaries and the insufficient segregation of B to the grain boundaries, induces grain boundaries to migrate and causes the abnormal grain growth. The increased bulk diffusion coefficient of B within Cu grains can be responsible for the normal grain growth occurring in the annealed $Cu(B)/Ti/SiO_2\;at\;600^{\circ}C$. In contrast, the $Cu/SiO_2$ structures show only the abnormal growth of grains and their sizes increasing as the temperature increases above $400^{\circ}C$.

Ca와 Zr을 소량 첨가한 나노결정 Fe-Si-B-Cu계 합금의 미세조직변화와 자기적특성

안수봉,장수환,박원욱,손근용 대한금속·재료학회 2021 대한금속·재료학회지 Vol.59 No.3

Nanocrystalline Fe-Si-B-Nb-Cu Finemet alloys show low saturation magnetic flux density compared to amorphous Fe-Si-B alloys. In the Fe-Si-B-Cu base amorphous alloys, Cu atoms form clusters which act as heterogeneous nucleation sites for α-Fe crystals. The addition of Ca element atoms, distributed along grain boundaries, helps inhibit grain growth and increase resistivity. These alloys can be crystallized into fine nanograins through proper heat treatment, with increased saturated flux density and decreased core loss. According to previous studies, the addition of Zr element can also reduce nanograin size and suppress grain growth by its distribution mainly along the grain boundaries. In this experiment, the effects of added Ca and Zr on the microstructural changes and magnetic properties of Fe-Si-B-Cu were evaluated in detail. Fe-Si-B-Cu alloys containing Ca, and Zr elements were melt-spun to make rapidly solidified ribbons ~20 μm in thickness. The ribbons were then wound into toroidal shaped ribbon cores and heat treated to obtain the nanocrystalline soft magnetic ribbon cores. The microstructure was observed using TEM, and the magnetic characteristics were evaluated using an B-H meter and impedance analyzer. Based on the results, the Fe- Si-B-Cu ribbon core containing 0.037 wt.% Ca and 1.68 wt.% Zr was determined to have the lowest core loss among the alloys, when annealed at 440 oC for 30 min. It was also confirmed that the added Ca and Zr elements were distributed along the grain boundary, and suppress the growth of crystals. In conclusion, the addition of minor elements Ca and Zr to the nanocrystalline ribbon core was very effective at reducing core loss, and the saturated flux density of the core also increased pronouncedly compared to the Fe-Si-B-Nb-Cu Finemet alloys.

Transformation Behavior of Ti-(45-x)Ni-5Cu-xCr (at%) (x = 0.5-2.0) Shape Memory Alloys

Yeon-Min Im,Young-Min Jeon,Min-Su Kim,Yong-Hee Lee,Min-Kyun Kim,남태현 한국전기전자재료학회 2011 Transactions on Electrical and Electronic Material Vol.12 No.1

Transformation behavior and shape memory characteristics of Ti-(45-x)Ni-5Cu-xCr (x=0.5-2.0) alloys have been investigated by means of electrical resistivity measurements, differential scanning calorimetry, X-ray diffraction and thermal cycling tests under constant load. Two-stage B2-B19-B19’ transformation occurred in Ti-(45-x)Ni-5Cu-xCr alloys. The B2-B19 transformation was separated clearly from the B19-B19’ transformation in Ti-44.0Ni-5Cu-1.0Cr and Ti-43.5Ni-5Cu-1.5Cr alloys. A temperature range where the B19 martensite exists was expanded with increasing Cr content because decreasing rate of Ms (85 K / % Cr) was larger than that of Ms’ (17 K / % Cr). Ti-(45-x)Ni-5Cu-xCr alloys were deformed in plastic manner with a fracture strain of 68% ~ 43% depending on Cr content. Substitution of Cr for Ni improves the critical stress for slip deformation in a Ti-45Ni-5Cu alloy due to solid solution hardening.

Transformation Behavior of Ti-(45-x)Ni-5Cu-xCr (at%) (x = 0.5-2.0) Shape Memory Alloys

Im, Yeon-Min,Jeon, Young-Min,Kim, Min-Su,Lee, Yong-Hee,Kim, Min-Kyun,Nam, Tae-Hyun The Korean Institute of Electrical and Electronic 2011 Transactions on Electrical and Electronic Material Vol.12 No.1

Transformation behavior and shape memory characteristics of Ti-(45-x)Ni-5Cu-xCr (x=0.5-2.0) alloys have been investigated by means of electrical resistivity measurements, differential scanning calorimetry, X-ray diffraction and thermal cycling tests under constant load. Two-stage B2-B19-B19' transformation occurred in Ti-(45-x)Ni-5Cu-xCr alloys. The B2-B19 transformation was separated clearly from the B19-B19' transformation in Ti-44.0Ni-5Cu-1.0Cr and Ti-43.5Ni-5Cu-1.5Cr alloys. A temperature range where the B19 martensite exists was expanded with increasing Cr content because decreasing rate of Ms (85 K / % Cr) was larger than that of Ms' (17 K / % Cr). Ti-(45-x)Ni-5Cu-xCr alloys were deformed in plastic manner with a fracture strain of 68% ~ 43% depending on Cr content. Substitution of Cr for Ni improves the critical stress for slip deformation in a Ti-45Ni-5Cu alloy due to solid solution hardening.

Fabrication and Soft Magnetic Properties of Fe–B–Si–Zr/Hf–Cu Nanocrystalline Alloys with High Glass-Forming Ability

Yaoxiang Geng,Yingmin Wang,Yuxin Wang,Zhijie Zhang,Hongbo Ju,Lihua Yu,Junhua Xu 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.11

The effects of minor alloying addition of Cu on the glass-forming ability and crystallization process of Fe71.7−xB16.7Si8.3Zr3.3Cuxand Fe72.5−xB16.7Si8.3Hf2.5Cux (x = 0, 0.3, 0.7, 1.0 and 1.3; at%) alloys were investigated. It was found that the critical glassformation size of rod samples gradually decreased from 2.5 to 1 mm with increasing Cu content in these alloys. Single α-Fe phase nanocrystalline alloys were obtained after isothermal annealing the Fe–B–Si–Zr/Hf–Cu glassy alloys containing0.7–1.0 at% Cu. The Fe71B16.7Si8.3Zr3.3Cu0.7alloy exhibited good soft magnetic properties with a high saturation magnetization(~ 1.22 T) and a low coercive force (~ 0.6 A/m) after annealing at 853 K for 10 min due to the precipitation of α-Fenanoparticles of 8 nm size in the glassy matrix. The structural evolution on annealing and the variation tendencies against Cucontent of the glass transition temperature, thermal stability and glass-forming ability of the Fe–B–Si–Zr/Hf–Cu amorphousalloys were discussed using a dual-cluster local structure model.

The B2-B19-B19’ Transformation in Ti-(45-x)Ni-5Cu-xMn (at%) (x = 0.5-2.0) Alloys

Yeong-Min Jeon,Min-Gyun Kim,Min-Su Kim,Yong-Hee Lee,Yeon-Min Im,남태현 한국전기전자재료학회 2011 Transactions on Electrical and Electronic Material Vol.12 No.1

Effect of substitution of Mn for Ni on transformation behavior, shape memory characteristics and superelasticity of Ti45Ni-5Cu alloy has been investigated by means of electrical resistivity measurements, X-ray diffraction, thermal cycling tests under constant load and tensile tests. The one-stage B2-B19’ transformation occurred when Mn content was 0.5 at%, above which the two-stage B2-B19-B19’ transformation occurred. A temperature range where the B19martensite exists was expanded with increasing Mn content because decreasing rate of Ms (60 K / % Mn) was larger than that of Ms’ (40 K / % Mn). Ti-(45-x)Ni-5Cu-xMn alloys were deformed in plastic manner with a fracture strain of 60 % ~ 32 % depending on Mn content. Clear superelasticity was found in fully annealed Ti-(45-x)Ni-5Cu-xMn alloys with Mn content more than 1.0 at%, which was ascribe to a solid solution hardening by substitution of Mn for Ni.

The B2-B19-B19' Transformation in Ti-(45-x)Ni-5Cu-xMn (at%) (x = 0.5-2.0) Alloys

Jeon, Yeong-Min,Kim, Min-Gyun,Kim, Min-Su,Lee, Yong-Hee,Im, Yeon-Min,Nam, Tae-Hyun The Korean Institute of Electrical and Electronic 2011 Transactions on Electrical and Electronic Material Vol.12 No.1

Effect of substitution of Mn for Ni on transformation behavior, shape memory characteristics and superelasticity of Ti45Ni-5Cu alloy has been investigated by means of electrical resistivity measurements, X-ray diffraction, thermal cycling tests under constant load and tensile tests. The one-stage B2-B19' transformation occurred when Mn content was 0.5 at%, above which the two-stage B2-B19-B19' transformation occurred. A temperature range where the B19 martensite exists was expanded with increasing Mn content because decreasing rate of Ms (60 K / % Mn) was larger than that of Ms' (40 K / % Mn). Ti-(45-x)Ni-5Cu-xMn alloys were deformed in plastic manner with a fracture strain of 60 % ~ 32 % depending on Mn content. Clear superelasticity was found in fully annealed Ti-(45-x)Ni-5Cu-xMn alloys with Mn content more than 1.0 at%, which was ascribe to a solid solution hardening by substitution of Mn for Ni.

Superelasticity and Corrosion Behavior of 50Ti–(45-X)Ni–5Cu–XMo (at.%) Alloys

Nam, Tae-Hyun,Jung, Dae-Won,Kim, Jae-Hoon,Liu, Yinong,Kim, Ki-Won,Jeong, Sang-Sik Sage Publications 2006 Journal of intelligent material systems and struct Vol.17 No.12

<P>In this study superelasticity and corrosion characteristics of 50Ti–(45-X)Ni–5Cu–XMo alloys have been investigated by means of electrical resistivity measurements, X-ray diffraction, tensile tests, polarization tests, and optical microscopy. Substitution of Mo for Ni in a Ti–45Ni–5Cu alloy induces the B2–B19 transformation and the stability of the B19 martensite increases with an increase in Mo content. Superelastic recovery of 50Ti–(45-X)Ni– 5Cu–XMo alloys increases from 33 to 91% with an increase in Mo-content from 0 to 0.5%. The 50Ti–(45-X)Ni–5Cu–XMo alloys show small stress hysteresis below 100 MPa. The pitting potential of 50Ti–(45-X)Ni–5Cu–XMo alloys also increases with the increase in Mo content.</P>

Microstructures and shape memory characteristics of rapidly solidified Ti₅₀Ni₃₀Cu₂₀ alloy ribbons

Kim, Yeon-Wook,Yun, Young-Mok,Nam, Tae-Hyun Elsevier 2006 Materials science & engineering. properties, micro Vol.438 No.-

<P><B>Abstract</B></P><P>Transformation behaviors and shape memory characteristics of Ti<SUB>50</SUB>Ni<SUB>30</SUB>Cu<SUB>20</SUB> (at.%) alloy ribbons prepared by melt spinning were investigated by means of differential scanning calorimetry, X-ray diffraction, and optical microscopy. The alloy was solidified as amorphous ribbon by a melt spinning process. After annealed at 440°C for 10min, the crystallized ribbon was deformed up to about 6.8% in ductile manner. A temperature hysteresis associated with the B2–B19 transformation was observed to be 4K. These properties are mainly attributed to the controlled microstructures of the alloy ribbon.</P>