Hyppää sisältöön
    • Suomeksi
    • På svenska
    • In English
  • Suomeksi
  • In English
  • Kirjaudu
Näytä aineisto 
  •   Etusivu
  • LUTPub
  • Väitöskirjat
  • Näytä aineisto
  •   Etusivu
  • LUTPub
  • Väitöskirjat
  • Näytä aineisto
JavaScript is disabled for your browser. Some features of this site may not work without it.

Nanoscale phenomena during joining, ageing treatment and abrasive wear of metallic materials : molecular dynamics study

Chen, Jiayi (2024-12-09)

Katso/Avaa
Jiayi Chen_A4.pdf (31.66Mb)
Lataukset: 


Väitöskirja

Chen, Jiayi
09.12.2024
Lappeenranta-Lahti University of Technology LUT

Acta Universitatis Lappeenrantaensis

School of Energy Systems

School of Energy Systems, Konetekniikka

Kaikki oikeudet pidätetään.
Näytä kaikki kuvailutiedot
Julkaisun pysyvä osoite on
https://urn.fi/URN:ISBN:978-952-412-184-2

Kuvaus

ei tietoa saavutettavuudesta

Tiivistelmä

The development of novel technologies contribute to the evolution of intelligent world, which significantly depends on the evolution of smart materials and progressive manufacturing technologies. For the sustainability of the ecosystem, utilizing cost-effective and sustainable materials and manufacturing processes is essential. Therefore, novel materials, e.g., shape memory alloys, and manufacturing processes used for fabricating engineering components for advanced applications, such as high-speed electric motors (synchronous reactance motor), and butterfly valves, are studied in this thesis. It is difficult to observe the nanostructure behaviour during the experiment, while the understanding of nanoscale phenomena provides clarity of material behaviours during manufacturing process. Therefore, simulations at the nanoscale are employed to study the in-depth material behaviour during manufacturing and the in-service conditions of those applications. The study provides insights into the nanostructural phenomena, aids in materials selection, explores manufacturing issues for practical applications.

Molecular dynamics (MD) models the behaviour of atoms in nanoscale, helping to understand materials properties in the areas of material science and nanotechnology. This thesis utilises the MD method for simulating nanoscale phenomena and material behaviours that are expensive and time consuming to study by experiments. The MD simulations are applied to study the nanoscale phenomena in the following three topics:

• Joining of Inconel and steel alloys through vacuum brazing for the electric motor rotor.

• Martensitic phase transformation in different grain-sizes of nitinol shape memory alloys during ageing.

• Phase transformations in different coating materials, e.g., steels, stellite 6, of a valve disc under abrasive wear.

The models show the atomic interactions of the material and give a more profound understanding of the material behaviours, which are in agreement with the experimental observations. The simulations demonstrate nanostructural phenomena during manufacturing, such as phase transformations, dislocations, and atomic diffusion, which show the process of structure evolution and cohesion relations between different materials. The simulation demonstrates and clarifies the issue of poor cohesion during rotor manufacturing, predicts the phase transformation temperatures of heat treated shape memory alloy, and phase transformations during the abrasive wear of different coating materials on valve disc during its operation.
Kokoelmat
  • Väitöskirjat [1123]
LUT-yliopisto
PL 20
53851 Lappeenranta
Ota yhteyttä | Tietosuoja | Saavutettavuusseloste
 

 

Tämä kokoelma

JulkaisuajatTekijätNimekkeetKoulutusohjelmaAvainsanatSyöttöajatYhteisöt ja kokoelmat

Omat tiedot

Kirjaudu sisäänRekisteröidy
LUT-yliopisto
PL 20
53851 Lappeenranta
Ota yhteyttä | Tietosuoja | Saavutettavuusseloste