Fabrication of A CU-AL-NI-MN Shape Memory Alloy

1991 ◽  
Vol 246 ◽  
Author(s):  
Ming H. Wu ◽  
S.L. Semiatin ◽  
L.M. Schetky
Keyword(s):  
Shape Memory ◽  
Recrystallization Texture ◽  
Rolling Direction ◽  
Rolling Process ◽  
Rolling Plane ◽  
Phase Region ◽  
Normal Direction ◽  
Β Phase ◽  
Memory Recovery ◽  
Hot Rolling Process

AbstractIn the development of an optimized hot rolling process for a Cu-Al-Ni-Mn sheet alloy, the effects of the recrystallization texture on ductility and shape memory recovery were examined. The texture of samples rolled in the β phase region (750 °C) was characterized by martensitic (128) poles along the normal direction and (0018) poles inclined 60° from the normal to the rolling direction. The texture of samples rolled in the α+β region (600 °C) was slightly stronger but less symmetric. The shape memory recovery was more or less isotropic in the rolling plane, independent of the rolling conditions. However, improved bend ductility of 9.5% was observed along the rolling direction in specimens rolled at 750 °C with a reduction per pass of 27%.

Slitting Criterion for Various Slitting Roll Geometry in MSR Rolling Process

2010 ◽  
Vol 165 ◽  
pp. 365-370
Author(s):  
Andrzej Stefanik ◽  
Piotr Szota ◽  
Sebastian Mróz ◽  
Henryk Dyja
Keyword(s):  
Numerical Analysis ◽  
Hot Rolling ◽  
Rolling Direction ◽  
Main Idea ◽  
Rolling Process ◽  
Critical Value ◽  
Rolling Speed ◽  
Hot Rolling Process ◽  
Slit Rolling ◽  
Single Strip

The main idea of multi slit rolling (MSR) technology is the capability of producing two, three, four and even five rods simultaneously from a single strip in a hot rolling process. Correct separation of the joined strips is one of the major problems in the MSR process. High tensile stresses (perpendicular to the rolling direction) are generated during movement of the band by the slitting rolls in the joining bridge. Critical value of the slitting criterion is mainly affected by geometry of the slitting rolls (angle, dimension and mass of the slitting rolls), temperature of the band and rolling speed. This paper presents results of numerical analysis of influence of the slitting roll angle on value of normalized Cockroft – Latham criterion during double slitting rolling process.

Self-Accommodating Nature of Martensite Formation in Shape Memory Alloys

2014 ◽  
Vol 213 ◽  
pp. 114-118
Author(s):  
Osman Adiguzel
Keyword(s):  
Martensitic Transformation ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Parent Phase ◽  
Alloy System ◽  
Phase Region ◽  
Martensite Formation ◽  
Martensite Variant ◽  
Β Phase ◽  
Phase Condition

Shape memory effect is a peculiar property exhibited by certain alloy system. This behavior is facilitated by martensitic transformation, and shape memory properties are intimately related to the microstructures of alloys; in particular, the morphology and orientation relationship between the various martensite variants. Martensitic transformation occurs in thermal manner, on cooling the materials from high temperature parent phase region. Thermal induced martensite called self-accommodated martensite or multivariant martensite occurs as multivariant martensite in self-accommodating manner and consists of lattice twins. Shape memory alloys are deformed in low temperature martensitic phase condition, and deformation proceeds through a martensite variant reorientation. Copper based alloys exhibit this property in metastable β - phase region.

Cast and Rolling Textures of NiMnGa Alloys

2007 ◽  
Vol 1050 ◽  
Author(s):  
Robert Chulist ◽  
Martin Poetschke ◽  
Andrea Boehm ◽  
Heinz-Guenter Brokmeier ◽  
Ulf Garbe ◽  
...  
Keyword(s):  
Recrystallization Texture ◽  
Room Temperature ◽  
Rolling Direction ◽  
High Energy ◽  
Growth Direction ◽  
Rolling Plane ◽  
Variant Selection ◽  
Directionally Solidified ◽  
Magnetic Shape Memory ◽  
Hot Rolled

AbstractThe texture of two polycrystalline NiMnGa magnetic shape memory alloys fabricated by directional solidification and hot rolling has been measured with high-energy synchrotron radiation and neutron diffraction. At room temperature the alloys used are composed of a modulated (7M) and non-modulated (NM) martensitic structure. The texture of the directionally solidified alloy for all phases is a pronounced fibre texture with <100> preferentially aligned along the growth direction. In the directionally solidified case a variant selection took place with [001] dominating. The texture of the hot rolled alloy shows a weak recrystallization texture with {111} and <112> aligned parallel to the rolling plane and rolling direction, respectively. The texture results are discussed with respect to material, processing and phase transformations including variant selection.

The Role of Twinned and Detwinned Structures on Memory Behaviour of Shape Memory Alloys

2015 ◽  
Vol 1105 ◽  
pp. 78-82 ◽  
Author(s):  
Osman Adiguzel
Keyword(s):  
High Temperature ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Parent Phase ◽  
Martensitic Transformations ◽  
Phase Region ◽  
Finish Temperature ◽  
Β Phase

Shape memory alloys have a peculiar property to return to a previously defined shape or dimension when they are subjected to variation of temperature. Shape memory effect is facilitated by martensitic transformation governed by changes in the crystalline structure of the material. Martensitic transformations are first order lattice-distorting phase transformations and occur with the cooperative movement of atoms by means of lattice invariant shears in the materials on cooling from high temperature parent phase region. The material cycles between the deformed and original shapes on cooling and heating in reversible shape memory effect. Thermal induced martensite occurs as twinned martensite, and the twinned martensite structures turn into detwinned structures by deforming the material in the martensitic condition. Deformation of shape memory alloys in martensitic state proceeds through a martensite variant reorientation. The deformed material recovers the original shape on first heating over the austenite finish temperature in reversible and irreversible shape memory cases. Meanwhile, the parent phase structure returns to the twinned structure in irreversible shape memory effect on cooling below to martensite finish temperature and to the detwinned structure in reversible shape memory effect. Therefore, the twinning and detwinning processes have great importance in the shape memory behaviour of the materials. Copper based alloys exhibit this property in metastable β-phase region, which has bcc-based structures at high temperature parent phase field, and these structures martensitically turn into layered complex structures with lattice twinning following two ordered reactions on cooling.

Closure behavior of spherical void in slab during hot rolling process

2018 ◽  
Vol 115 (3) ◽  
pp. 301 ◽  
Author(s):  
Rong Cheng ◽  
Jiongming Zhang ◽  
Bo Wang
Keyword(s):  
Plastic Strain ◽  
Hot Rolling ◽  
Rolling Direction ◽  
Element Model ◽  
Rolling Process ◽  
Slab Thickness ◽  
Hot Rolling Process ◽  
Roller Diameter ◽  
Width Direction ◽  
The Relationship

The mechanical properties of steels are heavily deteriorated by voids. The influence of voids on the product quality should be eliminated through rolling processes. The study on the void closure during hot rolling processes is necessary. In present work, the closure behavior of voids at the center of a slab at 800 °C during hot rolling processes has been simulated with a 3D finite element model. The shape of the void and the plastic strain distribution of the slab are obtained by this model. The void decreases along the slab thickness direction and spreads along the rolling direction but hardly changes along the strip width direction. The relationship between closure behavior of voids and the plastic strain at the center of the slab is analyzed. The effects of rolling reduction, slab thickness and roller diameter on the closure behavior of voids are discussed. The larger reduction, thinner slab and larger roller diameter all improve the closure of voids during hot rolling processes. Experimental results of the closure behavior of a void in the slab during hot rolling process mostly agree with the simulation results..

Indentation Measurement of CuZnAl Dual Phase Shape Memory Alloy

2018 ◽  
Vol 784 ◽  
pp. 38-43
Author(s):  
Marek Vojtko ◽  
Ján Balko ◽  
Martin Fides ◽  
Liudmila Vojtkova
Keyword(s):  
Mechanical Properties ◽  
Shape Memory ◽  
Indentation Test ◽  
Phase Region ◽  
Indentation Hardness ◽  
Indentation Modulus ◽  
Dual Phase ◽  
Quenching Temperature ◽  
Β Phase ◽  
Α Phase

The aim of this work is indentation study of local mechanical properties of Cu-22Zn-4.6Al alloy, which has significant shape memory effect after quenching from dual α + β phase region. The study was carried out on the samples with thermoelastic and non-thermoelastic martensite in the structure, which were obtained by quenching from various temperatures. A different behavior concerning mechanical properties measurements of α phase and β phase transformed to martensite after quenching from various temperatures was found out. It was observed almost no change of mechanical properties of α phase, whereas indentation hardness HIT and indentation modulus EIT raised with increasing quenching temperature. Also some serious differences were observed at indentation test of thermoelastic and non-thermoelastic martensite.

Numerical Simulation on Correcting Camber and Wedge of Steel Slabs in Hot Rolling Mill

2014 ◽  
Vol 626 ◽  
pp. 570-575 ◽  
Author(s):  
Jong Ning Aoh ◽  
Han Kai Hsu ◽  
Wei Ting Dai ◽  
Chun Yen Lin ◽  
Yen Liang Yeh
Keyword(s):  
Hot Rolling ◽  
Rolling Mill ◽  
Rolling Direction ◽  
Rolling Process ◽  
Element Analysis ◽  
Hot Rolling Process ◽  
Steel Slab ◽  
Hot Rolling Mill ◽  
Rolling Load

In the hot rolling process, the steel slab may experience a temperature gradient along its transverse direction which may cause camber and wedge after rolling. Camber and wedge phenomenon will affect the quality of the steel plate. To eliminate camber and wedge phenomenon, a pair of side guides is placed before and behind the hot rolling mill. The position mode and the force mode are the control modes for side guides to correct the slab shape and to guide the slab to follow rolling direction. Finite element analysis using ABAQUS was applied to simulate hot rolling process to find the correction mechanism of rolling equipment. The centerline of slab was traced and the shape of slab was predicted. The difference of rolling load between work side and drive side of roller was determined. Furthermore, the load, stress and velocity distribution on the slab at roll bite were analyzed. By using numerical model, hot rolling parameters including side guide control strategy can be predicted, which can provide the hot rolling line as a guideline to improve the quality of the steel slab.

Anisotropic fatigue behavior of rolled Mg–3Al–1Zn alloy

2010 ◽  
Vol 25 (5) ◽  
pp. 966-971 ◽  
Author(s):  
Seong-Gu Hong ◽  
Sung Hyuk Park ◽  
Yong-Hak Huh ◽  
Chong Soo Lee
Keyword(s):  
Plastic Deformation ◽  
Fatigue Life ◽  
Deformation Behavior ◽  
Fatigue Behavior ◽  
Rolling Direction ◽  
Rolling Plane ◽  
Normal Direction ◽  
Mean Stress ◽  
Stress Energy ◽  
Life Behavior

The anisotropy in the fatigue behavior of rolled Mg–3Al–1Zn alloy between the rolling direction and normal direction to the rolling plane was investigated. The {10-12} twinning–detwinning characteristics were found to play key roles in the anisotropic fatigue deformation behavior by inducing a change in the predominant plastic deformation mechanism, which controlled the flow stress and finally influenced the fatigue resistance by generating mean stress. Energy-based approach was successfully used to describe anisotropic fatigue life behavior.

Effect of Cold-Rolling Rate on Texture in Ti-Mo-Al-Zr Shape Memory Alloy

2013 ◽  
Vol 738-739 ◽  
pp. 262-266 ◽  
Author(s):  
Katsunori Hiramatsu ◽  
Masaki Tahara ◽  
Tomonari Inamura ◽  
Hideki Hosoda ◽  
Shuichi Miyazaki
Keyword(s):  
Shape Memory Alloy ◽  
Cold Rolling ◽  
Shape Memory ◽  
Recrystallization Texture ◽  
Thermomechanical Processing ◽  
Reduction Rate ◽  
Solution Treatment ◽  
Alloy System ◽  
Β Phase ◽  
Rolling Rate

Effect of rolling rate on texure of Ti-Mo-Al-Zr shape memory alloy was investigated using X-ray diffraction pole figure measurement and electron backscattering pattern (EBSP) analysis to optimize the thermomechanical processing. Ti-Mo-Al-Zr alloy is a candidate Ni-free shape memory alloy to replace Ti-Ni alloy in medical applications. The alloy was single phase of β before rolling and then α''-martensite was induced during the cold-rolling. Unlike the recrystallization texture in Ti-Nb alloy system, {110}ββ recrystallization texture of β-phase was developed by the solution-treatment especially in the specimens with the reduction rate higher than 90%. This texture has never been observed in Ti-Nb based alloys and can exhibit a larger recovery strain in both tension and compression.

Microstructure and Texture Evolution during Hot Rolling of Mg-9Li-7Al-1Sn Alloy for Aerospace Application

2011 ◽  
Vol 702-703 ◽  
pp. 85-88
Author(s):  
Vinod Kumar ◽  
R. Balasubramaniam ◽  
Rajiv Shekhar ◽  
Kantesh Balani
Keyword(s):  
Hot Rolling ◽  
Texture Evolution ◽  
Rolling Process ◽  
Grain Structure ◽  
Aerospace Application ◽  
Β Phase ◽  
Hot Rolling Process ◽  
Α Phase ◽  
Hot Rolled ◽  
Increased Activity

In the present work, Mg - 9wt. % Li - 7% wt. Al – 1 wt. % Sn (LAT971) alloy was cast and hot rolled at ~573K. Phase analysis of LAT971 revealed the presence of dual phase structure namely Mg-rich α- and Li-rich β-phase. After hot rolling, it was observed that dynamic recrystallization led to refinement of the α-phase grain structure. Significant crystallographic texture evolution, characterized by electron backscatterd diffraction, revealed increased activity of the non-basal (101 ̅0) slip plane after conventional hot rolling process.

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