Phase Formation, Thermal Stability and Mechanical Properties of a Cu-Al-Ni-Mn Shape Memory Alloy Prepared by Selective Laser Melting

Gargarella, Piter; Kiminami, Cláudio Shyinti; Mazzer, Eric M.; Cava, R.D.; Basilio, Leonardo Albuquerque; Bolfarini, Claudemiro; Eckert, J.; Gustmann, Tobias; Pauly, S.

doi:10.1590/1516-1439.338914

Cited by 40 publications

(13 citation statements)

References 10 publications

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“…1). This is in agreement with other reports on alloys with similar compositions [4,5,7,31,47], however, due to the detection limit of the XRD technique (generally a few wt.% [48]), we cannot exclude that very small volume fractions of additional phases are present. Apparently, the applied cooling rates are sufficiently high to suppress the formation of the c 2 and a phase.…”

Section: Resultssupporting

confidence: 93%

“…This behaviour is known as shapememory effect (SME) [1][2][3]. It is related to the reversible transformation of a low-temperature phase (martensite) to a high-temperature phase (austenite), which can be stressinduced or temperature-induced [1][2][3][4][5][6][7]. The four characteristic temperatures of this diffusionless phase transformation are A s , A f , M s and M f .…”

Section: Introductionmentioning

confidence: 99%

“…Hence, especially Cu-Al-Ni SMAs, which are less prone to ageing (i.e. the precipitation of c 2 or other phases) than Cu-Zn-Al SMAs for instance, with small grain sizes and enhanced deformability have been subject of research in the past decades [2,4,7,9,10,[18][19][20].…”

Section: Introductionmentioning

confidence: 99%

“…With decreasing grain size, the transformation temperatures of Cu-based SMAs have been found to become lower [2,4,5,10,16,18,20]. This makes SLM a very attractive tool for processing Cu-based SMAs because the resulting grain sizes are rather small and, hence, these specimens exhibit an improved deformability [7]. At the same time, sophisticated structures can also be produced by this approach, which are impossible to be created through casting [38].…”

Section: Introductionmentioning

confidence: 99%

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Properties of Cu-Based Shape-Memory Alloys Prepared by Selective Laser Melting

Gustmann¹,

Santos

Gargarella

et al. 2016

Shap. Mem. Superelasticity

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Two shape-memory alloys with the nominal compositions (in wt.%) Cu-11.85Al-3.2Ni-3Mn and Cu-11.35Al-3.2Ni-3Mn-0.5Zr were prepared by selective laser melting (SLM). The parameters were optimised to identify the process window, in which almost fully dense samples can be obtained. Their microstructures were analysed and correlated with the shape-memory behaviour as well as the mechanical properties. Suction-cast specimens were also produced for comparison. Mainly, b 1 0 martensite forms in all samples, but 0.5 wt.% of Zr stabilises the Y phase (Cu 2 AlZr), and its morphology depends on the thermal history and cooling rate. After annealing, the Y phase is primarily found at the grain boundaries hampering grain coarsening. Due to the relative high cooling rates applied here, Zr is mostly dissolved in the martensite in the as-prepared samples and it has a grainrefining effect only up to a critical cooling rate. The Zrcontaining samples have increased transformation temperatures, and the Y phase seems to be responsible for the jerky martensite-to-austenite transformation. All the samples are relatively ductile because they mostly fracture in a transgranular manner, exhibiting the typical double yielding. Selective laser melting allows the adjustment of the transformation temperatures and the mechanical properties already during processing without the need of a subsequent heat treatment.

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Section: Resultssupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Properties of Cu-Based Shape-Memory Alloys Prepared by Selective Laser Melting

Gustmann¹,

Santos

Gargarella

et al. 2016

Shap. Mem. Superelasticity

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“…Slow equilibrium cooling causes the precipitation of stable phases, which would inhibit the martensitic transformation and therefore the SME 9 . Processes with a high cooling rate can be usually employed not only to ensure the β' 1 phase formation but also to efficiently reduce the grain size and therefore improve the mechanical properties 13,[16][17][18][19] . An economical and efficient way to apply high cooling rates of up to 10 10 K/s is laser surface remelting 20 .…”

Section: Introductionmentioning

confidence: 99%

Microstructural Characterization of a Laser Surface Remelted Cu-Based Shape Memory Alloy

et al. 2018

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Cu-based shape memory alloys (SMAs) present some advantages as higher transformation temperatures, lower costs and are easier to process than traditional Ti-based SMAs but they also show some disadvantages as low ductility and higher tendency for intergranular cracking. Several studies have sought for a way to improve the mechanical properties of these alloys and microstructural refinement has been frequently used. It can be obtained by laser remelting treatments. The aim of the present work was to investigate the influence of the laser surface remelting on the microstructure of a Cu-11.85Al-3.2Ni-3Mn (wt%) SMA. Plates were remelted using three different laser scanning speeds, i.e. 100, 300 and 500 mm/s. The remelted regions showed a T-shape morphology with a mean thickness of 52, 29 and 23 µm and an average grain size of 30, 29 and 23µm for plates remelted using scanning speed of 100, 300 and 500 mm/s, respectively. In the plates remelted with 100 and 300 mm/s some pores were found at the root of the keyhole due to the keyhole instability. We find that the instability of keyholes becomes more pronounced for lower scanning speeds. It was not observed any preferential orientation introduced by the laser treatment.

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