The crystallographic and morphological evolution of the strengthening precipitates in Cu–Ni–Si alloys

Discontinuous precipitates in age-hardening CuNiSi alloys

“…The extra spots and streaks in the SAED pattern shown in Fig. 2(c) can be assigned to the ordered δ-Ni 2 Si with an orthorhombic structure [13,14]. We can identify, therefore, that the fine disk-shaped CPs are composed of a δ-Ni 2 Si phase.…”

“…To date, the age-hardening precipitates in the alloys have been widely accepted as being δ-Ni 2 Si intermetallics with an orthorhombic structure [6][7][8][9][10][11][12][13][14][15][16][17], although other types of precipitates, such as β-Ni 3 Si, (Cu,Ni) 3 Si, and other metastable phases, might coexist [8,[12][13][14][15]. In their most recent study, Hu et al investigated the subsequent age-hardening of δ-Ni 2 Si precipitates (i.e., continuous precipitates (CPs)) that form during isothermal aging, and explained their behavior using classical theories of phase transformation in association with energy calculations [14]; the CPs in Cu-2.6 Ni-1.6 Si-0.5 Cr (in at.%) alloys did not exhibit any changes in their δ-Ni 2 Si crystal structure, but underwent changes in their morphology and other crystallographic features. There were basically two types of δ-Ni 2 Si precipitates in the alloys, namely, δ 1 -Ni 2 Si and δ 2 -Ni 2 Si.…”

“…The precipitating phase responsible for the age-hardening has been investigated by a number of researchers, especially regarding the early stages of aging [6][7][8][9][10][11][12][13][14][15]. To date, the age-hardening precipitates in the alloys have been widely accepted as being δ-Ni 2 Si intermetallics with an orthorhombic structure [6][7][8][9][10][11][12][13][14][15][16][17], although other types of precipitates, such as β-Ni 3 Si, (Cu,Ni) 3 Si, and other metastable phases, might coexist [8,[12][13][14][15].…”

Synthesis, characterization and DFT calculations of electronic and optical properties of YbPO 4

“…Today, theoretical studies have become effective methods to study the electronic structure, optical properties, crystallographic evolution, morphology and the reaction mechanism [10][11][12][13][14]. Recently, density functional calculations are used to investigate the enthalpies of formation of rare-earth monophosphates and to make a comparative analysis of their experimental and theoretical vibrational properties [15,16].…”

Recrystallization Texture and Shear Band Formation in Bending

“…In this study, to focus on the (iii), we employed polycrystalline samples of high-concentration Cu-Ni-Si alloys with various recrystallization textures. The Cu-Ni-Si system is an alloy with high hardness due to δ-Ni 2 Si precipitation [23][24][25][26] . To observe in detail the inhomogeneous deformation associated with the change of surface shape, the FE-SEM/EBSD method was used.…”