Damage evolution in pseudoelastic polycrystalline Co–Ni–Ga high-temperature shape memory alloys

Electron beam welding of Fe–Mn–Al–Ni shape memory alloy: Microstructure evolution and shape memory response

“…Even grain boundary fracture can occur. 10,15,16 Recent studies showed that by adjusting the morphology and orientation of grains and grain boundaries with respect to the loading direction functional properties can be significantly improved in SMA systems. [16][17][18][19][20] In these studies, it was shown that an optimal ratio between grain size and sample size leads to significantly increased shape recovery following pseudoelastic deformation.…”

“…10,15,16 Recent studies showed that by adjusting the morphology and orientation of grains and grain boundaries with respect to the loading direction functional properties can be significantly improved in SMA systems. [16][17][18][19][20] In these studies, it was shown that an optimal ratio between grain size and sample size leads to significantly increased shape recovery following pseudoelastic deformation. [16][17][18][19][20] Omori and coworkers proposed a cyclic heat treatment, leading to abnormal grain growth (AGG) in Cu-Al-Mn and Fe-Mn-Al-Ni SMAs, resulting in a so-called bamboo-like microstructure, which is characterized by grain boundaries having a predominant alignment perpendicular to the loading direction.…”

“…[16][17][18][19][20] In these studies, it was shown that an optimal ratio between grain size and sample size leads to significantly increased shape recovery following pseudoelastic deformation. [16][17][18][19][20] Omori and coworkers proposed a cyclic heat treatment, leading to abnormal grain growth (AGG) in Cu-Al-Mn and Fe-Mn-Al-Ni SMAs, resulting in a so-called bamboo-like microstructure, which is characterized by grain boundaries having a predominant alignment perpendicular to the loading direction. 4,20,21 These bamboo-like microstructures exhibit distinctly improved functional properties.…”

“…1,2,16,23 Therefore, many studies have been conducted in order to understand the role of microstructures on functional properties of SMAs. 1,2,[15][16][17][18][19][20][21][22][23][24] In this regard, weakly textured SMAs often show rapid functional and structural degradation due to pronounced grain constraints between favored and non-favored grains in terms of transformability. 8,16,25,26 In particular, due to highly anisotropic material properties, most SMAs suffer from incomplete shape recovery as a result of defect generation at grain boundaries imposed by the grain constraints as well as defect generation at austenite-martensite phase boundaries and at martensite variant boundaries.…”

“…1,2,[15][16][17][18][19][20][21][22][23][24] In this regard, weakly textured SMAs often show rapid functional and structural degradation due to pronounced grain constraints between favored and non-favored grains in terms of transformability. 8,16,25,26 In particular, due to highly anisotropic material properties, most SMAs suffer from incomplete shape recovery as a result of defect generation at grain boundaries imposed by the grain constraints as well as defect generation at austenite-martensite phase boundaries and at martensite variant boundaries. 10,15,16,18,19 In numerous studies focusing on the pseudoelastic performance of a broad variety of SMAs, it was found that microstructural appearance, i.e.…”