Influence of Cobalt on the Hot Deformation Characteristics of an NiTi Shape Memory Alloy

Santosh, S.; Praveen, R.; Sampath, Santosh

doi:10.1007/s12666-019-01591-6

Cited by 23 publications

(8 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The LAGB fraction reflects the dynamic softening ability of the alloy, and the LAGBs indicate that most of the dislocations disappear through climbing or rearrangement, resulting in the decrease in the deformation energy and resistance. However, because the location of the deformation condition of 390 °C/1 s −1 is at the unsafe region in the processing map, the fraction of LAGBs does not conform to the law of change [ 37 ]. Because the deformation of microstructure in the unsafe region is severe, fragmented grains form at the triangular region between the deformed grains, increasing the local deformation distortion energy and the fraction of LAGBs caused by static recrystallization, and even possibly forming shear bands [ 38 ].…”

Section: Resultsmentioning

confidence: 99%

Constitutive Analysis and Microstructure Characteristics of As-Homogenized 2198 Al–Li Alloy under Different Hot Compression Deformation Conditions

Yan

et al. 2023

Materials

View full text Add to dashboard Cite

The 2198 Al–Li alloy has unique superiority in mechanical performance and has been extensively used in the aerospace field. In this study, the hot deformation behavior of the 2198 Al–Li alloy was investigated on a Gleeble-1500 thermomechanical simulator with a strain rate of 0.01–10 s−1 in the temperature range of 330–510 °C. The Arrhenius constitutive equation of the alloy was established based on the true stress–strain curves to describe the rheology behaviors during the deformation of the alloy. The processing maps under the strain of 0.2–0.8 were constructed, which indicates the efficiency of power dissipation and instability of the deformed alloy. It was found that the instability domains are more likely to occur in the regions of low deformation temperature and high strain rate, corresponding to the high Zener–Hollomon (Z) parameter. The microstructure evolution of the studied alloy with different Z parameters was characterized. Then, the dynamic recrystallization (DRX) behavior was studied by electron backscatter diffraction, and the misorientation angle of deformed specimens was analyzed. The effect of different deformation temperatures and strain rates on the microstructure of the alloy and the behavior of dislocations and precipitations were investigated by transmission electron microscopy. The results demonstrate that continuous dynamic recrystallization (CDRX) and geomatic dynamic recrystallization (GDRX) mainly occur at the deformation conditions of a low Z value, and discontinuous dynamic recrystallization (DDRX) is likely to occur with increasing Z values.

show abstract

Section: Resultsmentioning

confidence: 99%

Constitutive Analysis and Microstructure Characteristics of As-Homogenized 2198 Al–Li Alloy under Different Hot Compression Deformation Conditions

Yan

et al. 2023

Materials

View full text Add to dashboard Cite

show abstract

“…The method used to highlight the austenitic grain is the method of controlled oxidation and is done as follows: A flat face of the sample must be sanded, and the rest must show no signs of oxidation [ 9 , 13 ]; The sample is placed in the oven with the surface sanded up and is kept for 1 h at the austenite temperature provided for each quality of material; then open the oven door and leave the sample in its door for about 10–15 s for oxidation, then place the iron in water; In the case of significant oxidation, the oxide adhering to the polished surface is easily removed by grinding with fine sandpaper, after which the sample is attacked with Villella reagent (1 g picric acid, 5 mL hydrochloric acid, 100 mL ethyl alcohol) [ 14 , 15 , 16 , 17 , 18 , 19 ] …”

Section: Methodsmentioning

confidence: 99%

“…In the case of significant oxidation, the oxide adhering to the polished surface is easily removed by grinding with fine sandpaper, after which the sample is attacked with Villella reagent (1 g picric acid, 5 mL hydrochloric acid, 100 mL ethyl alcohol) [ 14 , 15 , 16 , 17 , 18 , 19 ]…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Experimental Research for the Establishment of the Optimal Forging and Heat Treatment Technical Parameters for Special Purpose Forged Semi-Finishes

et al. 2023

View full text Add to dashboard Cite

The authors present in this paper the experimental results and conclusions obtained after conducting a comparative study on three samples of forged semi-finished products from the steel brands 10CrMo9-10, 25CrMo4, and 42CrMo4. These are common heat-resistant alloy steels used in various industries nationally and internationally. This study aimed to test under the same identical experimental conditions of forging and heat treatment of three samples made of three different brands of steels 10CrMo9-10, 25CrMo4, and 42CrMo4. Analyzing the experimental results obtained, it can be seen for which of the three brands of tested steels the best forging and heat treatment parameters are obtained. Following experimental research, the best material was determined by analyzing the results obtained for the mechanical characteristics (tensile tests according to DNVGL-RP0034-SFC2 and NACE MR0175–hardness 207-235 HBW) and austenitic grain size. The authors determined that among the three types of steels analyzed, 10CrMo9-10 best meets the imposed requirements. This statement is in view of the comparative analysis of the results of experimental research.

show abstract

“…Cobalt is an efficient means for the adjustment of these properties. Estimations of the effect of cobalt on the shape memory parameters and mechanical properties of monolithic materials, based on TiNi for medical purposes, were published in the literature [7][8][9][10]. Phukaoluan et al showed that the addition of 3% Co in a TiNi alloy can increase the loading-unloading force of TiNi wire due to the increase in phase fraction austenite.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Cobalt on the Deformation Behaviour of a Porous TiNi-Based Alloy Obtained by Sintering

et al. 2021

View full text Add to dashboard Cite

This research investigates the effect of cobalt on the deformation behaviour of a porous TiNi-based alloy that was obtained by sintering. Porous TiNi-based alloys with cobalt additives, accounting for 0–2 at. % and with a pitch of 0.5, were obtained. The structural-phase state of the porous material was researched by X-ray structural analysis. The effect of different amounts of Co (used as an alloying additive) on the deformation behaviour was investigated by tensile to fracture. The fractograms of fracture of the experimental samples were analysed using scanning electron microscopy. For the first time, the present research shows a diagram of the deformation of a porous TiNi-based alloy that was obtained by sintering under tensile. The stages of deformation were described according to the physical nature of the processes taking place. The effect of the cobalt-alloying additive on the change in the critical stress of martensitic shear was investigated. It was found that the behaviour of the concentration dependency of stress at concentrations under 1.5 at. % Co was determined by an increase in the stress in the TiNi solid solution. This phenomenon is attributed to the arrangement of Co atoms on the Ti sublattice, as well as an increase in the fraction of the B19′ phase in the matrix. The steep rise of the developed forces on the concentration dependency of the martensitic shear stress at 2 at. % Co is presumably attributed to the precipitation hardening of austenite due to the precipitation of finely dispersed coherent Ti3Ni4 phase following the decrease of fraction of martensite. An analysis of fractograms showed that as more cobalt was added, areas of fracture with traces of martensite plates of the B19′ phase started to prevail. At 2 at. % Co these plates fill almost the entire area of the fracture. The research findings presented in this work are of great importance, since they can be used to achieve the set of physical and mechanical properties required for the development of biocompatible materials for implantology.

show abstract

Influence of Cobalt on the Hot Deformation Characteristics of an NiTi Shape Memory Alloy

Cited by 23 publications

References 13 publications

Constitutive Analysis and Microstructure Characteristics of As-Homogenized 2198 Al–Li Alloy under Different Hot Compression Deformation Conditions

Constitutive Analysis and Microstructure Characteristics of As-Homogenized 2198 Al–Li Alloy under Different Hot Compression Deformation Conditions

Experimental Research for the Establishment of the Optimal Forging and Heat Treatment Technical Parameters for Special Purpose Forged Semi-Finishes

The Effect of Cobalt on the Deformation Behaviour of a Porous TiNi-Based Alloy Obtained by Sintering

Contact Info

Product

Resources

About