Strain-Induced Reverse Phase Transformation in Nanocrystalline Co-Ni Alloys

Figures & data

Figure 1. Phase diagram of Co-Ni.[12]

Table 1. Composition of electroplating baths used in the present study.

	(mol·l^−1)
	0.87, 0.98, 1.09
	0.30, 0.20, 0.10
Boric acid	0.50
Saccharin	2.5(g·l^−1)
Sodium dodecyl sulfate	0.5(g·l^−1)

Table 2. Pulse plating conditions leading to acceptable nanocrystalline Co-Ni deposits from saccharin-containing electrolyte.

Parameter	Value
On-time (ms)	30
Off-time (ms)	270
Peak current density (mA·cm^−2)	200
Temperature (°C)	40
pH	4.0

Figure 2. Initial structure (1.bright-field, 2.dark-field, 3.SAED, 4.XRD) of as-deposited samples with different nickel contents: (a) Co-20.6at%Ni; (b) Co-31.0at%Ni and (c) Co-48.0at%Ni.

Figure 3. Typical tensile engineering stress–strain curves under a tensile rate of 0.5 mm/min: (a) free-standing sample; (b) sample together with substrate; (c) 304 stainless steel substrate and (d) curve of deposit layer estimated by ROM. The inset shows the geometry of tensile samples (R, radius of curvature).

Figure 4. Bight-field TEM images of Co-31.0at%Ni after different tensile tests: (a)  = 0.35% (free-standing sample); (b)  = 0.6%; (c)  = 1.0%; (d)  = 1.4% and (e)  = 1.5%.

Figure 5. Structure of Co-31.0at%Ni samples after tensile failure up to  = 1.5%: (a) overall bright-field image; (b) bright-field image of the grown grains; (c) SAED pattern corresponding to the background; (d) SAED pattern corresponding to the grains grown up, which is measured by nano-beam diffraction (NBD) model and (e) X-ray diffraction pattern.

Nishizawa T, Ishida K. The Co-Ni (Cobalt-Nickel) system. Bull Alloy Phase Diagr. 1983;4(4):390–395. doi: 10.1007/BF02868090

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