List of symbols and abbreviations ............................... V
List of tables ................................................ VII
List of figures ................................................. X
List of equations .............................................. XX
1 Introduction and Motivation .................................. 1
2 Literature Review ............................................ 5
2.1 TRIP-steel .............................................. 5
2.2 Zirconia ............................................... 12
2.2.1 Introduction .................................... 12
2.2.2 Stabilisation of zirconia ceramics .............. 15
2.2.3 Magnesia stabilised zirconia .................... 21
2.2.4 Yttria stabilised zirconia ...................... 22
2.2.5 Ceria stabilised zirconia ....................... 23
2.2.6 Calcia stabilised zirconia ...................... 24
2.3 Metal matrix Composites ................................ 26
2.3.1 Types and Classification of composites .......... 26
2.3.2 Processing of metal matrix composites ........... 27
2.3.3 PM-Composite materials in the system TRIP-
steel-ZrO2 ...................................... 30
2.3.4 Plastic processing of TRIP-steel/zirconia
composite materials ............................. 33
2.3.4.1 Shaping ................................ 33
2.3.4.2 Organic additives and binder burnout ... 34
2.3.5 Interactions in the system TRIP-steel/zirconia .. 39
2.3.5.1 General aspects ........................ 39
2.3.5.2 Iron ................................... 42
2.3.5.3 Nickel ................................. 45
2.3.5.4 Chromium ............................... 47
2.3.5.5 Manganese .............................. 50
2.3.5.6 Titanium ............................... 57
3 Experimental ................................................ 61
3.1 Raw materials .......................................... 61
3.1.1 Zirconia ........................................ 61
3.1.2 TRIP-steel powder ............................... 63
3.1.3 Alloying elements and metal dopants ............. 64
3.1.4 Oxide additions ................................. 65
3.2 Sample preparation - general aspects ................... 66
3.3 Plastic processing of TRIP-matrix composites ...... 67
3.4 Binder burnout experiments ........................ 68
3.5 Experimental setup - interactions during thermal
treatment ......................................... 69
3.6 Methods of Characterisation ............................ 72
3.6.1 Thermal analysis ................................ 72
3.6.2 Physical and mechanical properties .............. 73
3.6.3 X-ray Diffraction ............................... 74
3.6.4 EBSD Analysis ................................... 76
3.6.5 Microstructure .................................. 77
4 Results I - PM processed MMC ................................ 78
4.1 Investigations on plastic processing route ............ 78
4.1.1 General aspects ................................. 78
4.1.2 Extrusion - Square cell honeycomb structures .... 79
4.1.3 Extrusion - bulk material ....................... 82
4.1.4 Thermal debinding ............................... 83
4.1.4.1 Introduction ........................... 83
4.1.4.2 Binder burnout of cellular materials ... 86
4.1.4.3 Binder burnout of bulk materials ....... 91
4.1.5 Sintering ....................................... 91
4.1.6 Conclusions ..................................... 96
4.2 Mechanical and microstructural testing of MMC .......... 97
4.2.1 Cellular TRIP-matrix composite structures ....... 97
4.2.2 Bulk materials ................................. 100
4.2.3 Interfacial reactions .......................... 100
5 Results II - TRIP-steel/zirconia interactions .............. 103
5.1 Investigations of zirconia low temperature sintering .. 103
5.1.1 Characterisation of magnesia partially
stabilised zirconia ............................ 103
5.1.1.1 Physical and mechanical properties .... 103
5.1.1.2 Microstructural characterisation ...... 105
5.1.2 Investigations on yttria stabilised zirconia ... 108
5.1.3 Summary of the undoped sintering ............... 109
5.2 Sintering zirconia with metal powder additions ........ 111
5.2.1 General review - Mg-PSZ ........................ 111
5.2.2 Introduction of iron particles in Mg-PSZ ....... 112
5.2.3 Introduction of chromium particles in Mg-PSZ ... 115
5.2.4 Introduction of nickel particles in Mg-PSZ ..... 118
5.2.5 Introduction of manganese particles in Mg-PSZ .. 120
5.2.6 Interactions of YSZ with Cr and Mn additions ... 128
5.2.7 Influence of the metal doping .................. 130
5.3 Investigation of common additives on zirconia low
temperature sintering ................................. 131
5.3.1 General aspects ................................ 131
5.3.2 Zirconia doped with magnesia aluminate spinel .. 132
5.3.3 Zirconia doped with titanium and titania ....... 133
5.3.4 Conclusions .................................... 135
5.4 Investigations on manganese stabilised zirconia ....... 136
5.4.1 Preliminary considerations ..................... 136
5.4.2 Mechanical and physical properties ............. 136
5.4.3 Microstructural characterisation ............... 137
5.4.4 Thermal investigations of manganese doped
zirconia ....................................... 142
5.4.5 Aging of manganese stabilised zirconia ......... 145
6 Summary and outlook ........................................ 147
7 List of literature ......................................... 152
A Appendix ................................................... 169
| 
