Abstract

Porous Ti-rich Ti-Ni alloy based composites with near-zero thermal expansion (NZTE) behaviour tailored by micro-sized SiC particles were fabricated using powder metallurgy and a two-step designing strategy. At first, the Ni concentration was tuned to broaden the temperature range of negative thermal expansion (NTE) of porous Ti-Ni alloys; then micro-sized SiC particles of different amounts were introduced and co-sintered with mixed Ti and Ni powders having an optimized atomic ratio so as to obtain SiC/Ti-Ni composites with desirable thermal expansion performance. Results show that there is a clear correlation between the reverse martensitic transformation and NTE temperature range. The porous 12wt.%SiC/Ti-43.8at.%Ni composite exhibits very low coefficient of thermal expansion (CTE) of -0.976×10 −6 K −1 from 114.08 to 131.50 °C. It is proposed that the NTE behavior originates from the volume change accompanying the phase transition of the Ti-Ni matrix, and the NZTE performance of SiC/Ti-Ni composites is attributed to the combination of the NTE produced by the alloy matrix and the positive thermal expansion provided by the SiC phase.

Highlights

  • For the porous Ti-Ni alloys, Titanium and Nickel powders (50 and 61 ȝm respectively, 99.9% purity) with a nominal atomic ratio of 100-x to x (42

  • The negative thermal expansion (NTE) temperature ranges (ƸTNTE) with –ve Į obtained by DIL and values of Įaverage over the corresponding NTE temperature ranges are listed

  • It can be found that all porous Ti-Ni alloys undergo an expected austenite transformation and present NTE effect in the testing range of 30-200 °C

Read more

Summary

Introduction

For the porous Ti-Ni alloys, Titanium and Nickel powders (50 and 61 ȝm respectively, 99.9% purity) with a nominal atomic ratio of 100-x to x (42

Results
Conclusion

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.