Phase Equilibria in the Ni-Co-Mn SystemAlexandre Alves Silva, Gabriel Ribeiro

Co-worker: Dongnan Li; Researcher: Yang Zhou; Instructor: Philip Nash ENGR-498-31.16M

Acknowledgements:John Hasier, Kathy Ho, Mary Hawgood, Russ Janota

Overview

Methods

Discussion

Results

SEMa) Ni50Co40Mn10

References

XRDNi50Co20Mn30

Optical Microscopy

Objectives • Determination of phase equilibria• Establish the phase diagram experimentally• Experimental verification of the Curie

temperature of Ni-Co-Mn alloys that have low percentage of Mn

ApplicationsThis kind of alloy has the shape memory effect, that has uses in different fields[1]:• Industrial: aircraft, spacecraft, robots, pipes and

telecommunications• Medical: bones, reinforcement of arteries and

veins, dental wires

DSC

Ni30Co50Mn10 zoomed in x100, x500 and x1000 (1000C HT)[1] Investigation on Ni-Co-Mn System – Xingye Dai (2016)

[2] Co-Mn-Ni Isothermal Section of Ternary Phase Diagram http://materials.springer.com/isp/phase-diagram/docs/c_2000200 (Springer-Verlag GmbH, Heidelberg, © 2014) Accessed: 30-06-2016

As expected all the samples analyzed showed only one phase in the SEM and in the Optical Microscopy, in other words they are all homogenous like presented in the Co-Mn-Ni Ternary Phase Diagram found in Springer Materials database. The TG & DSC tests indicate that during cooling from 1000°C, certain precipitation is occuring, which needs more future work to verify.

Average compositions obtained by SEM:a) Ni49.17Co40.40Mn10.43

b) Ni30.71Co59.43Mn9.86

c) Ni14.94Co74.87Mn10.18

d) Ni69.23Co10.03Mn20.74

b) Ni30Co60Mn10

For this research it was used 12 different sample compositions of the Ni-Co-Mn alloy as showed in this ternary phase diagram[2]

c) Ni15Co75Mn10 d) Ni70Co10Mn20

Ni50Co40Mn10 zoomed in x100, x500 and x1000 (1000C HT)

2 theta theta d a

Peak 1 43.5 21.75 2.0793 3.601453

Peak 2 50.64 25.32 1.801608 3.603217

Peak 3 74.4 37.2 1.274398 3.604542

Peak 4 90.28 45.14 1.086999 3.605167

To find the global lattice parameter (a), a plot of the local “a” vs “cos²q” is made by linear fit. The lattice parameter a can thus be determined from the intersection by extrapolation method.