Welding shape memory alloys with NdYAG lasers

Quintino, L.; Miranda, Rosa Maria Mendes

doi:10.1590/s0104-92242012000300005

Cited by 12 publications

(4 citation statements)

References 11 publications

(11 reference statements)

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“…No entanto, a maior parte dos trabalhos publicados além de fazerem uso do processo LBW, correspondem a união de fi os fi nos de LMF NiTi (diâmetros até 1mm) (4,(23)(24)(25)(26)30) . Existem poucos trabalhos realizados com chapas fi nas (espessuras entre 0,5 mm e 1 mm) de LMF NiTi, a maior parte deles sendo bastante recentes (19)(20)(21)(22)27,30) .…”

Section: Introductionunclassified

Estudo de juntas soldadas a laser de chapas finas de liga com memória de forma NiTi austenítica

Melo

Lima²,

Oliveira³

et al. 2017

RBAV

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ResumoLigas com memória de forma (LMF) de NiTi são materiais inteligentes que possibilitam o desenvolvimento de diversas aplicações de engenharia devido suas propriedades funcionais chamadas de efeito de memória de forma e superelasticidade. No entanto, fabricar componentes com geometria complexa a partir destes materiais é um desafio tecnológico que poderá ser superado com o desenvolvimento de técnicas efetivas de união destas ligas por soldagem. Objetivou-se neste trabalho avaliar os efeitos dos diferentes parâmetros de soldagem nas propriedades mecânicas de juntas soldadas obtidas de chapas finas de uma LMF de NiTi austenítica. As soldagens foram realizadas pelo processo de soldagem à laser (LBW -Laser Beam Welding) variando a potência e velocidade de soldagem e a realização ou não do tratamento térmico pós-soldagem (TTPS). Como ferramenta de otimização foi utilizado um planejamento experimental 2 3 e a metodologia da superfície de resposta. Foi observado que o TTPS promoveu a estabilização de um estado misto de fases na chapa de NiTi, entre a fase R e a austenita à temperatura ambiente e que após a soldagem foi possível observar uma redução dos valores aferidos de dureza no metal de solda (MS). Além disso, as juntas soldadas com velocidade de soldagem de 900 mm/min e que foram submetidas ao TTPS apresentaram resistência mecânica à tração satisfatória independentemente da potência empregada. Palavras-chave:Ligas com memória de forma, Ligas de NiTi, Processo de soldagem a laser. AbstRActNiTi shape memory alloys (SMA) are smart materials that enable the development of various engineering applications due to their functional properties called shape memory effect and superelasticity. However, to manufacture components with complex geometry from these materials is a technological challenge that can be overcome with the development of effective joint techniques of these alloys by welding. The objective of this work was to evaluate the effects of the different welding parameters on the mechanical properties of welded joints of thin sheets of austenitic NiTi SMA. The joints were performed by the laser welding process varying the power and speed of welding and the influence of post-weld heat treatment (PWHT) was verified. As an optimization and evaluation tool, a design of experiments and the response surface methodology were respectively used. It was observed that the PWHT promoted the stabilization of a phase mixed state in the thin sheet, between the R phase and the austenite at room temperature and that after welding it was possible to observe a reduction of the average values of hardness in the weld metal (WM). Furthermore, welded joints with welding speed of 900 mm/min and were submitted to PWHT showed satisfactory tensile mechanical strength independent of the welding power used.

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Section: Introductionunclassified

Estudo de juntas soldadas a laser de chapas finas de liga com memória de forma NiTi austenítica

Melo

Lima²,

Oliveira³

et al. 2017

RBAV

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“…The formation of various undesirable phases in the FZ of specimen 3 could be due to the migration of Ni from TiNi base alloy to liquid Ti in the weld pool, which favoured the formation of Ti 2 Ni type phases. Quintino et al 40 reported a similar structure (flowery) (Ti 2 Ni) during laser welding which can be observed in Figure 7 (e). The difference in microstructures in FZ could be attributed to variable cooling rates in the same welding environment.…”

Section: Resultsmentioning

confidence: 58%

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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“…A paper published by Quintino et al [6] also delves into the occupational safety and health issues specific to the welding environment. It emphasizes the importance of risk assessment, hazard control measures, and the role of safety management systems in preventing accidents.…”

Section: Introductionmentioning

confidence: 99%

“…It emphasizes the importance of risk assessment, hazard control measures, and the role of safety management systems in preventing accidents. Key findings highlight the need for effective hazard communication and monitoring of exposure levels to protect workers [6]. The American Conference of Governmental Industrial Hygienists (ACGIH) [7] also discusses the health effects of welding processes and provides exposure limits for various welding fumes and gases.…”

Section: Introductionmentioning

confidence: 99%

Antecedents of Safety and Health in the Workplace: Sustainable Approaches to Welding Operations

Belmoro,

Gumasing

2023

Sustainability

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Assessing the occupational health and safety (OHS) factors in the welding process is necessary to determine the workers’ perception of what contributes to their safety and health in the workplace. This would provide insight for stakeholders to aid them in their occupational safety and health programs. The non-probability sample technique utilized in this study is purposive sampling using an online survey. Welders in Singapore are the intended participants. The self-administered online survey was conducted using Google Forms. The hypothesis test’s beta coefficient and R2 results were used to evaluate the model using partial least squares structural equation modeling (PLS-SEM). The study’s results revealed that safety culture has the highest association with top management attitudes toward safety and health in the workplace. Similarly, safety training was also found to have a strong association with employees’ attitudes towards safety. Finally, factors such as compliance with safe working conditions, safety programs, and the absence of and lack of exposure to harmful agents were also proven to have a significant association with safety and health in the workplace. This study benefits not only those businesses conducting the welding process but also employees to better understand the factors contributing to their overall safety at work.

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Welding shape memory alloys with NdYAG lasers

Cited by 12 publications

References 11 publications

Estudo de juntas soldadas a laser de chapas finas de liga com memória de forma NiTi austenítica

Estudo de juntas soldadas a laser de chapas finas de liga com memória de forma NiTi austenítica

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

Antecedents of Safety and Health in the Workplace: Sustainable Approaches to Welding Operations

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