COST 507 - Repositório Aberto da Universidade do Porto

More documents

Recommendations

Info

Ti 2 (Va,N)! which yields Ti^ as a realistic end-member. This was accepted by Zeng et al. The β phase was modelled as Ti.(Va,N) 3 in all assessments and that is the usual choice for a bcc phase. The experimental information on α+β close to the transition point for pure Ti seems to be well established by Palty [54Pal] but the peritectic equilibria for L+δ—»a and L+a—»β are more uncertain. The main difficulty in the high Ti region seems to be the Οί/δ equilibrium where Jonsson chose to rely on data from Wolff et al. [85Wol], Etchessahar et al. [84Etc] and Lengauer et al. [88Len], whereas Zeng et al. trusted Palty [54Pal] and two tielines from a more recent unpublished work by Lengauer [91 Len]. They also claim to have used the information from another study by Lengauer et al. but that is not indicated by the result of their assessment. Both assessments yield fairly straight and parallel phase boundaries. Jonsson's two-phase field is narrow and falls inside the wider two-phase field by Zeng et al. In their discussion they seem to agree with Jonsson on what the maximum Ν content of α should be at temperatures around 1300 K, where intermediary phases appear, but they would need a temperature dependent interaction parameter in the α phase in order to reconcile such high Ν contents with the lower Ν contents according to the two tie-lines by Lengauer [91 Len] which fall at about 1600 and 1900 K. However, they did not try to do this. Instead, they claim that their description is supported by information on two intermediary phases, ζ and η, and unpublished information on the Ti-Ni-N system , Friec et al. [95Fri]. 2.5 Intermediary Ti-N phases An ε phase of an approximate composition Ti 2 N is stable below about 1338 K. It is usually proposed to form by a peritectoid reaction but Wriedt et al. [87Wri] emphasised that the probable position of the (α+δ)/δ phase boundary would result in a congruent transition ε—>δ if the composition of ε is Ti 2 N. Evidently, the phase diagram could be modified in three ways to yield a peritectoid reaction, (1) by assuming that ε at its highest temperature has less Ν than according to TiN 2 , (2) by moving the (α+δ)/δ phase boundary to higher Ν contents, (3) by introducing another intermediary phase above the ε phase. Zeng et al. considered it a very important conclusion that ε does not form congruently from δ and they wanted the phase diagram to show this. Indeed, they were able to predict a peritectoid transformation by accepting the higher Ν contents of the (α+δ)/δ boundary, indicated by Lengauer's [91 Len] two tie-lines, and the existence of a new intermediary phase, η. On the other hand, from a practical point of view, it does not seem very important to reproduce the correct reaction for ε. It may be more important to establish the composition of ε by new experiments. In particular, it does not seem justified to accept the higher Ν content of the (α+δ)/δ phase boundary from Lengauer's [91 Len] two tie-lines just because it contributes to the suppression of the congruent transformation point of ε under the assumption that ε is Ti 2 N. Lengauer and Ettmayer [88Len] first found the two new intermediary phases, ζ-Τί 4 Ν 3 . χ and η-Τϊ 3 Ν 2 . χ , existing close to the maximum temperature of ε and reacting with ε in two ways each. Zeng et al. reproduced the reported reaction temperatures - 176 -
with high precision whereas Jonsson chose not to include them in his assessment. It should also be mentioned that an ordered δ phase, denoted by δ, has been reported. It is natural to expect that δ should order at low temperatures, primarily with Ti 2 N! as the ideal composition. However, the information on δ is not quite clear and Zeng et al. proposed that δ only occurs as a metastable phase. They did not include it in their assessment, nor did Jonsson. When comparing the assessments of the Ti-N system by Jonsson and by Zeng et al., the inclusion of the ζ and η phases in the latter one may look as a major difference. However, they can probably be easily added to Jonsson's description without changing the parameters of the other phases if the experimental temperatures and compositions are accepted. On the other hand, it is puzzling that two phases should occur so close to each other and in such a narrow range of temperature. An independent check of the range of existence of all three, δ, ε and η, is needed before their role in the Ti-N phase diagram can be assessed with any certainity. It may be added that more information is also needed for the ordered δ phase. Jonsson's assessment of the whole Ti-N system is thus preferred in the present work. 3. Application of the descriptions of TiN and Ti-N to higher order systems G m of TiN and the description of the Ti-N system should then be tested against information on higher-order systems of direct interest. In this case one should examine the Fe-Ti-N and Al-Ti-N systems. 3.1 The Fe-Ti-N system Due to its technical importance the solubility of TiN in fcc-Fe has been examined many times and several equations for its variation with temperature have been proposed, [60Gur], [62Ada], [75Nar], [78Mat], [85Wad], [89Tur] and [82Kun]. See Table 1. These data can be compared with values calculated termodynamically by Jonsson [97Jon]. His value agrees well with Kunze [82Kun] and falls below Wada and Pehlke [85Wad] by a factor of about 2. However, it must be remembered that the termodynamic calculation depends on the descriptions of Ν in fcc-Fe and of Ti in fcc- Fe. The Fe-N system is probably well established, Frisk [91 Fri], but not the Fe-Ti system. Jonsson made similar calculations for L-Fe and δ-bcc-Fe finding a deviation of about 3 on the higher side, see Figs.3 and 4. To improve this requires a modification of the Fe-Ti system. A recent assessment, made by Saunders [97Sau], gave a good fit of the solubilities in L, see Fig.4, and bcc but lowered the solubility product in fee by a factor of about 6. That would be closer to old measurements. See also the last value in Table I. TiN may be non-stoichiometric and that should increase its stability. However, that effect was already taken into account in Figs.3 and 4. In summary, it may be stated that Saunders has shown that the experimental - 177 -
Page 1 and 2:
European Commission COST European c
Page 5 and 6:
European Commission COST European c
Page 7:
Preface The Final Workshop of the C
Page 11 and 12:
COST 507 STRUCTURE Measurement and
Page 13:
GRl: Mirtee S.A., Volos Mr.P.Polati
Page 16 and 17:
D9 Dll Fl GR2 II NI S3 SF1 "Thermop
Page 19 and 20:
A Summary of the COST 507 Action an
Page 21 and 22:
Aluminium-based systems Titanium-ba
Page 23 and 24:
An Example using the COST 507 Datab
Page 25 and 26:
Appendix COST 507: Some Key Meeting
Page 27 and 28:
Al - 0.5 Fe, 1 Mg, 0.8 Mn, 0.2 Si (
Page 29 and 30:
Fig 4 Aluminium beverage cans. The
Page 31:
Fig 6 High pressure compressor vane
Page 34 and 35:
INTRODUCTION All of us are aware of
Page 36 and 37:
In the interaction with materials a
Page 38 and 39:
There was a first warning more than
Page 40 and 41:
Some time ago, the well-known physi
Page 42 and 43:
Today there is a whole range of ins
Page 44 and 45:
The dimension of this reservoir inc
Page 46 and 47:
REFERENCES [ 1 ] G. Petzow, "Man, M
Page 48 and 49:
Trends in Application of Materials
Page 50 and 51:
Raw Materials The Cycle of Material
Page 52 and 53:
i LÌ i.'»Af·· iù^ VV.V.X. iTTa
Page 54 and 55:
1600 OJ 1200 .« 1100 d 1000 900 Si
Page 57 and 58:
Al Phase Relations in the Aluminium
Page 59 and 60:
oundaries of the single phase regio
Page 61 and 62:
Table 1 : Crystallographic Data of
Page 63 and 64:
order to facilitate the evaluation
Page 65 and 66:
(especially around 33 at% Mg) in or
Page 67 and 68:
3.System Ti-Sn-Al-N. The investigat
Page 69 and 70:
6) N.Durlu, U.Gruber, M.Pietzka, H.
Page 71 and 72:
Summary of final report Directional
Page 73 and 74:
calculate the thermodynamic mixing
Page 75 and 76:
Introduction It is the aim of this
Page 77 and 78:
Thermodynamic evaluations for high
Page 79 and 80:
Figure 5 presents the calculated li
Page 81 and 82:
There is a complete lack in the lit
Page 83 and 84:
a.B5 ø.ia 0.15 0.20 0.25 0.30 0.35
Page 85 and 86:
700 [53Phi] 800 +[90Kuz21 ]iquld a
Page 87 and 88:
Thermodynamic Assessments, Experime
Page 89 and 90:
AIN and TiNi_ x is also given. Vari
Page 91 and 92:
satisfied the three requirements of
Page 93 and 94:
84Bey R. Beyers, R. Sinclair, and M
Page 95 and 96:
Material and Methods 2.1 Fabricatio
Page 97 and 98:
3.4 Electronmicroscopy (SEM) and X-
Page 99 and 100:
Tab. 3: Density of the Ti20Albase
Page 101 and 102:
Tab.5. continued TÌ20A1 5CulONi Ti
Page 103 and 104:
Fig. 3: ESMA and Xray diffraction
Page 105 and 106:
Fig.7: Wetting angle of Ti 15A1 lOC
Page 107 and 108:
Thermophysical Properties of Light
Page 109 and 110:
Tab.2 Chemical composition of terna
Page 111 and 112:
700 (AI)+AIFeS¡«_600 KS1275.1 l
Page 113 and 114:
4.2 Thermal conductivity of industr
Page 115 and 116:
4.3 AlSiZn alloys Electrical re
Page 117 and 118:
94Jar/Bra G.Jaroma-Weiland, R.Brand
Page 119 and 120:
MgZn9 (C 14) and Mg2Zn u in the Al
Page 121 and 122:
The three Laves phases were describ
Page 123 and 124:
References [13Ege] G. Eger, Z. Meta
Page 125 and 126:
0.30 0.35 0.40 0.45 0.50 mole fract
Page 127 and 128:
□ [48Koe] 600 500 400 0 0.1 0
Page 129 and 130: MggZn,, this work □ Single phase,
Page 131 and 132: Temperatures in °C 0.05 0.10 mole
Page 133 and 134: Table 2 : Alloy compositions Alloy
Page 135 and 136: All. Dy 50 Cpexp °C Cpadd Table 5
Page 137 and 138: Zn ¿Kl Si Fig. 2 : Position of the
Page 139 and 140: 22.5 ■■ 7.5 Temperature ICI Tem
Page 141 and 142: .to 2.5 "lõõ soo iÍOõ dOõ rtõ
Page 143 and 144: GR2 Differential Scanning Calorimet
Page 145 and 146: Time (x10 3 sec) Fig. 1. DSC Thermo
Page 147 and 148: solidification. It can be seen that
Page 149 and 150: 4. Conclusions Differential scannin
Page 151 and 152: COST 507 - ROUND Π UNIT II SEZIONE
Page 153 and 154: [96Sac] The Rrich regions of the
Page 155 and 156: List of publications in the framewo
Page 157 and 158: 2Contributions: oral or posters p
Page 159 and 160: 1996 REPORT 2 s ' PART: ACTIVITY CA
Page 161 and 162: [96Sei] Excess Gibbs energy coeffic
Page 163 and 164: List of publications in the framewo
Page 165 and 166: Proc. :7 th Meeting on "Syntheses a
Page 167 and 168: 2.1 Solid solubility measurements T
Page 169 and 170: eviews by Rivlin and Raynor [81 Riv
Page 171 and 172: inaires. Thesis, Universite Scienti
Page 173 and 174: Table 1. Review of the ternary phas
Page 175 and 176: L) Liq+bcc=FeSi+t_1 M) Liq+t 1=FeSi
Page 177 and 178: Extrapolations based on Ti-C-N S3 B
Page 179: value has been accepted in all thre
Page 183 and 184: only fit the hightemperature asym
Page 185 and 186: Jonsson combined his descriptions o
Page 187 and 188: Table II. Solubility product of TiC
Page 189 and 190: Ti-C, Z.Metallkd. 86 (1995) 5 319
Page 191 and 192: 1000 1500 2000 2500 3000 Τ (K) Fig
Page 193 and 194: o Oí o 3 4 5 6 7
Page 195 and 196: M^øD^ O Kelley(1944) • Kelley an
Page 197 and 198: — cale, with Dumitrescu (1997) -
Page 199 and 200: € gfc-π m-, .-π-, π-π .-saa J
Page 201 and 202: +graph 0 TiN 0.2 0.4 0.6 X TiC 0.8
Page 203 and 204: Binder et al (1992) TiN 1423 K ■
Page 205 and 206: 0.08 600°C 700°C 800°C 900°C 10
Page 207 and 208: [59Sto]: Ä600°C □ 70D°C O8Q0°
Page 209 and 210: 2000 Cale, with Saunders (1997) —
Page 211 and 212: An Experimental Investigation of th
Page 213 and 214: An Experimental Investigation of th
Page 215 and 216: 211 -
Page 217 and 218: EXPERIMENTAL INVESTIGATION OF THE C
Page 219 and 220: Fig.1 SEM micrographs of CuMgZr
Page 221 and 222: ■ 888 24 HSM^«" 16—19 3 À I
Page 223 and 224: Thermodynamic Evaluations of the Al
Page 225 and 226: Fcc_Al aves_C15 ONU ΔΝ12 αΝ13
Page 227 and 228: 2.2 Assessment The optimisation of
Page 229 and 230: 0.50 0.45 CulOZr7/ 0. 40 Or ^ 0.3
Page 231 and 232:
References [71Kri] Kripyakevich, P.
Page 233 and 234:
Kejun Zeng and Marko Hämäläinen,
Page 235 and 236:
for detennining phase boundary and
Page 237 and 238:
Table 2 Al-Fe-Mn results wt%Fe 0.5
Page 239 and 240:
•00 Γ Ι I I I ~ LIQUID S^ 7iO
Page 241 and 242:
the observed A2-B2 ordering. This p
Page 243 and 244:
1473K Ahmed & Flower [94 Ahmi] 0.2
Page 245 and 246:
900K Paruchuri & Massalski [91Par]
Page 247 and 248:
BCC_B2#2 TI3RL TIPL BCC B2#2 TIRL
Page 249 and 250:
0.2 0.3 0.4 0.5 X(LIQ,V) Figure 15
Page 251 and 252:
1 Introduction and Overview of the
Page 253 and 254:
at least 95% by Fe, possibly 99%, a
Page 255 and 256:
8 References 43Phi H W L Phillips,
Page 257 and 258:
1050 1000 Isopleth, Al - Si - 4 wt
Page 259 and 260:
Al-Mn-Si 873 K 0.90 Liquid 0.80 0.7
Page 261 and 262:
A Thermochemical Assessment of Data
Page 263 and 264:
certainly due to the appearance of
Page 265 and 266:
Materials Science Centre, November
Page 267 and 268:
1400 Al-Mn Fig 2 Calculated partial
Page 269 and 270:
1000 ι AlMn I Ι 950 Liquid E ω
Page 271 and 272:
Al-Fe-Mn 843 K 0.90 0.80 0.70 0.60
Page 273 and 274:
AlFeMn section at 2 wt% Mn co
Page 275:
0.50 0.45 0.40-1 LU £ 0.35 LU 0.30
Page 279:
European Commission EUR 18171 —CO
Page 284:
NOTICE TO THE READER Information on
show all

COST 507 - Repositório Aberto da Universidade do Porto

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?