Effect of Heat Treatments on Thermomechanical Properties of Additively Manufactured Ti6Al4V alloy at Elevated Temperatures and Correlation with Microstructure for Aerospace and Defense application / (Record no. 613953)
[ view plain ]
| 000 -LEADER | |
|---|---|
| fixed length control field | 05020nam a22001577a 4500 |
| 082 ## - DEWEY DECIMAL CLASSIFICATION NUMBER | |
| Classification number | 670 |
| 100 ## - MAIN ENTRY--PERSONAL NAME | |
| Personal name | Ali, Nouman |
| 245 ## - TITLE STATEMENT | |
| Title | Effect of Heat Treatments on Thermomechanical Properties of Additively Manufactured Ti6Al4V alloy at Elevated Temperatures and Correlation with Microstructure for Aerospace and Defense application / |
| Statement of responsibility, etc. | Nouman Ali |
| 264 ## - PRODUCTION, PUBLICATION, DISTRIBUTION, MANUFACTURE, AND COPYRIGHT NOTICE | |
| Place of production, publication, distribution, manufacture | Islamabad : |
| Name of producer, publisher, distributor, manufacturer | SMME- NUST; |
| Date of production, publication, distribution, manufacture, or copyright notice | 2025. |
| 300 ## - PHYSICAL DESCRIPTION | |
| Extent | 94p. |
| Other physical details | Soft Copy |
| Dimensions | 30cm. |
| 500 ## - GENERAL NOTE | |
| General note | Additive manufacturing (AM), being the future of the aerospace manufacturing industry,<br/>is famous for manufacturing rapidly, saving material, time and capital. Among metal AM<br/>processes, Selective Laser Melting (SLM) is the most used Powder Bed Fusion (PBF) technology<br/>and known for manufacturing near net shape parts with highest density. For aerospace and<br/>terrestrial applications, Ti alloys are considered to give balanced mechanical properties and<br/>Ti6Al4V is the most famous and most employed Ti alloy, attributed as the Ti workhorse especially<br/>in the aerospace industry. Its high strength to weight ratio, high corrosion resistance, high fatigue<br/>performance and excellent fracture toughness has been proven. Whereas its low thermal<br/>conductivity and high reactivity at elevated temperatures poses challenges during conventional<br/>manufacturing process including machining and casting. Thus, to avoid these demerits, the AM of<br/>Ti6Al4V and investigation of its mechanical properties has been the focus of research for the last<br/>two decades.<br/>In this research the thermomechanical properties of selectively laser melted (SLMed)<br/>Ti6Al4V have been studied with and without heat treatments and thermal properties at higher<br/>temperatures have been investigated to find out the reasons for low thermal conductivity through<br/>microstructure analysis and relative density measurements. The effect of different heat treatments<br/>with varying temperatures i.e. 900°C, 930°C and 950°C and dwell time i.e. 2 and 4 hours on<br/>thermomechanical properties have also been examined. Moreover, the effect of SLM build and<br/>scan orientation on thermal conductivity has been analyzed. The microstructure analysis has been<br/>performed through various qualitative and quantitative techniques including Optical Microscopy<br/>(OM), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and X-Ray<br/>Diffraction (XRD) analysis. The findings of microstructure investigations in terms of elemental<br/>composition, phase identification and grain morphology and relative density attained through<br/>different heat treatments have been correlated with heat treatment parameters and resulting<br/>thermomechanical properties.<br/>The thermal conductivity of heat treated SLMed Ti6Al4V has shown slightly improved<br/>range of values i.e. 2.47-2.85W/mK as compared to as-built stress relieved Ti6Al4V and shown<br/>linear relationship with thermal conductivity range of 2.47-4.86W/mK with an increase in<br/>temperature from RT to 300°C. The thermal conductivity of as-built stress relieved Ti6Al4V in<br/>scan orientation has given higher values of 2.98W/mK as compared to build orientation value of<br/>2.33W/mK. Findings show that heat treatment with temperature of 930°C and dwell of 2 hours<br/>given balance mechanical properties of high ductility i.e. 14.6% and optimum tensile strength<br/>859MPa, whereas Hot Isostatic Pressing (HIP) has significantly enhanced the thermal<br/>conductivity to 2.85W/mK. HIP treatment achieved the highest relative density as compared to all<br/>heat treatments i.e. 99.5%. Whereas the relative density increased from 97.6% to 98.98% with an<br/>increase in temperature and dwell time of heat treatments up to 930°C and decreased at 950°C i.e.<br/>96.79% which probably resulted in decreased thermal conductivity values.<br/>xi<br/>The wide scatter in thermal conductivity i.e. 2.11W/mK to 6.5W/mK, at RT by different methods,<br/>i.e. steady state method and transient plane source (TPS) methods observed by couple of<br/>researchers has been investigated by performing measurements through both methods. Results of<br/>steady state and TPS methods showed the similar thermal conductivity of as-built stress relieved<br/>Ti6Al4V i.e. 2.33W/mK and 2.41W/mK respectively at RT. It suggests that this wide variation<br/>found in literature was probably due to variation in metal AM process parameters used by different<br/>researchers and not because of measuring methods. The TPS method has given slightly higher<br/>values because it is probably less affected by surface roughness and possible oxide layers on<br/>surface.<br/>Overall, the hot isostatically pressed (HIPed) selectively laser melted (SLMed) Ti6Al4V in<br/>scan orientation has the capability to give highest thermal conductivity values for aerospace<br/>applications but with a compromise in mechanical strength due to layered manufacturing. |
| 650 ## - SUBJECT ADDED ENTRY--TOPICAL TERM | |
| Topical term or geographic name entry element | MS Design and Manufacturing Engineering |
| 700 ## - ADDED ENTRY--PERSONAL NAME | |
| Personal name | Dr. Muhammad Rizwan Ul Haq |
| 856 ## - ELECTRONIC LOCATION AND ACCESS | |
| Uniform Resource Identifier | <a href="http://10.250.8.41:8080/xmlui/handle/123456789/53338">http://10.250.8.41:8080/xmlui/handle/123456789/53338</a> |
| 942 ## - ADDED ENTRY ELEMENTS (KOHA) | |
| Source of classification or shelving scheme | |
| Koha item type | Thesis |
| Withdrawn status | Permanent Location | Current Location | Shelving location | Date acquired | Full call number | Barcode | Koha item type |
|---|---|---|---|---|---|---|---|
| School of Mechanical & Manufacturing Engineering (SMME) | School of Mechanical & Manufacturing Engineering (SMME) | E-Books | 06/27/2025 | 670 | SMME-TH-1139 | Thesis |