Effects of Heat Input on Weld-Bead Geometry, Surface Chemical Composition, Corrosion Behavior and Thermal Properties of Fiber Laser-Welded Nitinol Shape Memory Alloy

Saha, Partha; Datta, Susmita; Raza, Mohammad Shahid; Pratihar, Dilip Kumar

doi:10.1007/s11665-019-04077-0

Cited by 15 publications

(9 citation statements)

References 54 publications

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“…And this will result in a larger crater [22]. It is known that low welding speed increases the penetration [5], as the speed increases, penetration depth changed from full penetration to partial penetration mode [23]. Low welding speeds have already been used (1 cm/min and 2 cm/min) in this study.…”

Section: Resultsmentioning

confidence: 95%

304 Paslanmaz çeliğin mikroyapı ve mekanik özellikleri üzerinde yüksek enerjili lazer kaynak parametrelerinin etkisi

İrizalp¹,

Koroglu²

2021

Deu Muhendislik Fakultesi Fen Ve Muhendislik

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Autogenous bead-on-plate laser welding was performed on 2 mm 304SS materials at different heat inputs. The influence of laser energy in low welding speeds on weld performance using a Nd:YAG laser was studied. The weld performance was characterized in terms of weld bead morphology, microstructure and mechanical properties. The result revealed that the crater increased with the increase of heat input, so there is a linear relationship between crater and heat input. The gradual increase of the heat input was not directly related to the penetration of the weld bead. At the highest heat input, weld beads considerably expanded and also the crater deepened, the hardness increased in these joints while tensile strength and ductility reduced. The best mechanical properties were obtained with high laser energy at intermediate heat input. These weldments exhibited better strength even better than base metal 304SS. The microhardness values were distributed homogeneously from the fusion zone to the base metal. Laser energy increased the ferrite network and brought finer ferrites. As a result, usable laser welding parameters in terms of good strength, as well as good ductility and weld bead morphology were defined for welding 304 SS with 2 mm thickness.

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Section: Resultsmentioning

confidence: 95%

304 Paslanmaz çeliğin mikroyapı ve mekanik özellikleri üzerinde yüksek enerjili lazer kaynak parametrelerinin etkisi

İrizalp¹,

Koroglu²

2021

Deu Muhendislik Fakultesi Fen Ve Muhendislik

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“…18 However, LBW produced narrow BW and HAZ width compared to the DPTIG welding. 9,27 Microstructure. The microstructure of BM and FZ had a B2 austenite phase.…”

Section: Metallurgical Characterizationmentioning

confidence: 99%

“…A similar observation was seen in LBW, GMAW, TIG, and resistance welding of Nitinol. 25,26,27,37 The gray-scale mapping of the FZ, interface zone, and HAZ of the lowest HI welding trial is presented in Supplementary Figure 8. The microstructure is controlled by the composition of NiTinol, temperature gradient, and solidification rate.…”

Section: Metallurgical Characterizationmentioning

confidence: 99%

The effect of heat input on weld-bead geometry, mechanical, phase transformation temperature, and corrosion properties of autogenous double pulse TIG welded nitinol sheets

Manoj Samson,

Deepan Bharathi Kannan,

Shravan Kumar

2024

Proceedings of the Institution of Mechanical Engineers, Part E:

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This research aims to analyze the welding of 1 mm thick NiTinol sheets using an autogenous double pulse tungsten inert gas (DPTIG) welding process. The effect of heat input (HI) on bead geometry, microstructure, hardness, tensile strength, phase transformation temperature (PTT), and corrosion behavior was studied. The lower (111.25 J/mm), and higher (120.14 J/mm) HI produced an average grain size of 26 μm and 36 μm, respectively. The microstructure of the fusion zone (FZ) had coarser columnar grains with intermetallic phases such as Ni3Ti, and TiO2. The grain size in the FZ increased with the increase in HI. Sample P (111.25 J/mm) showed a higher hardness of 280.54 HV and tensile strength of 566 MPa due to a higher proportion of austenite phase (99.4%), the smaller grain size of 26 µm, a larger fraction of high angle grain boundary (HAGB) of 75.8%, and higher kernel average misorientation (KAM) value of 4.93. Compared to base metal (BM), sample P (111.25 J/mm), and sample S (120.14 J/mm) exhibited a reduction in tensile strength of 19.14% and 32.29%, respectively. The decline in hardness and tensile strength was attributed to the formation of intermetallic phases, a decrease in the Ti/Ni ratio, coarser grain formation, and a decrease in HAGB fraction and KAM values. The fractured tensile samples showed a mixed mode of fracture with dimples and cleavage facets. Compared to BM, Sample Q (118.05 J/mm) exhibited lesser variation in temperature hysteresis values for austenite and martensite temperatures, with a deviation of 0.4°C and 3.1°C, respectively. All the welded samples had better corrosion behavior than the BM due to a higher Ti/Ni ratio.

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“…Moreover, similar XRD spectra have been reported previously in the literature. 27,36,[43][44][45] Micro-hardness profile Micro-hardness profiles were measured and plotted across the weld zone, the heat-affected zone (HAZ), and the base alloy. A clear trend of rising hardness from the base alloy to the weld zone can be observed for all the specimens despite some instability in the measured values as shown in Figure 9.…”

Section: Microstructural Characterizationmentioning

confidence: 99%

Effect of welding current on the microstructure, residual stresses, mechanical properties and nano-mechanical behaviour of P-TIG welded TiNi binary shape-memory alloy

Asif

Khan

Shehbaz

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part L:

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In the present work, an autogenous TIG welding technique was used to join 2 mm thick sheets of a TiNi binary shape-memory alloy at three different values of current (80 A, 90 A and 100 A). The effects of the welding current on microstructures, residual stresses, mechanical properties and nano-mechanical behaviour were investigated. Microstructure analysis revealed that with an increase in current, the columnar grain size decreased, which had a significant effect on mechanical properties. The tensile strength of the weldment at 100 A was ∼92% of that base alloy’s (BA) and elongation of approx. 14%. The reduction in elongation was due to the formation of Ti2Ni and Ti3Ni4 type precipitates. The microhardness profile in all the weldments showed an increase of approx. 30% between the base alloy and the fusion zone due to the formation of Ti2Ni and Ti3Ni4 type precipitates during welding. Residual stress analysis suggested the tensile residual stresses in the longitudinal direction are minimum in the weldment performed at 100 A. The nanoindentation results revealed that the weldment obtained at 100 A had the least plastic deformation (∼45.5% less than the 80 A weldment) owing to a decrease in inter-dendritic spacing and high proportion of IMCs: Ti2Ni and metastable Ni4Ti3.

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Effects of Heat Input on Weld-Bead Geometry, Surface Chemical Composition, Corrosion Behavior and Thermal Properties of Fiber Laser-Welded Nitinol Shape Memory Alloy

Cited by 15 publications

References 54 publications

304 Paslanmaz çeliğin mikroyapı ve mekanik özellikleri üzerinde yüksek enerjili lazer kaynak parametrelerinin etkisi

304 Paslanmaz çeliğin mikroyapı ve mekanik özellikleri üzerinde yüksek enerjili lazer kaynak parametrelerinin etkisi

The effect of heat input on weld-bead geometry, mechanical, phase transformation temperature, and corrosion properties of autogenous double pulse TIG welded nitinol sheets

Effect of welding current on the microstructure, residual stresses, mechanical properties and nano-mechanical behaviour of P-TIG welded TiNi binary shape-memory alloy

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