The relationships of the compounds in the Mg-Ti-Al-O system in equilibrium with molten iron are investigated at temperatures ranging from 1873 to 1973 K, and the thermodynamic calculations are conducted in avoiding Al 2 O 3 or spinel MgAl 2 O 4 formation and for inclusion control. The equilibrium relations between the compounds (Mg 2 TiO 4 , MgTi 2 O 4 , or MgAl 2 O 4 ) and the composition of solutes in steel are clarified. The conditions are shown that the transformation of the stable compound from Mg-Ti spinel to Mg-Al spinel occurs at Mg contents ranging from 1 to 10 ppm by mass. It is also found, on the Mg-Ti spinel, the stable compound is transformed from inverse-spinel Mg 2 TiO 4 to normal-spinel MgTi 2 O 4 at Ti ¼ about 60 ppm by mass. In addition, the stable compound is transformed from MgTi 2 O 4 to Ti 2 O 3 at Ti ¼ about 1000 ppm by mass.

MoSi (in Fe) , is determined to be 43(Ϯ13) from the equilibrium for silicon distribution between Fe and Ag phases in Fe-Ag-Si-Mo system. The experimental results on the deoxidation equilibrium of molten Fe-Mo alloy with silicon reasonably agree with the calculated ones by using e Mo Si (in Fe) ϭ43(Ϯ13) derived in the present study. The oxygen contents after the deoxidation treatment by silicon are estimated for 8 kinds of steel. The oxygen content of ferrous alloys including molybdenum can be reasonably estimated using the interaction parameter of Mo for Si derived in the present study.

It is important to study the complex deoxidation equilibrium of molten iron in Ti-Mg-Al system from the view point of inclusion control. The equilibrium experiments between molten iron and TiO X -MgO-Al 2 O 3 slag and the thermodynamic calculation on the complex deoxidation are conducted at 1 973 K in the present study. The liquid phase region of TiO X -MgO-Al 2 O 3 system in equilibrium with molten iron is clarified at 1 973 K. The equilibrium compounds which are coexisted with the slag on the liquidus curve in the system are identified to be but the study on this system is very limited, and the phase equilibrium relations have not been clarified yet.In the present study, the liquid phase region of TiO X -MgO-Al 2 O 3 system in equilibrium with molten iron is investigated at 1 973 K. The equilibrium relation between the deoxidation products (Mg 2 TiO 4 or MgAl 2 O 4 ) and the composition of solute elements in steel is investigated, and the conditions that Mg 2 TiO 4 forms instead of MgAl 2 O 4 nor Al 2 O 3 are examined in the complex deoxidation of Ti-Mg-Al system. ExperimentalAn induction furnace was used for the deoxidation of high-purity electrolytic iron. The electrolytic iron in an alumina crucible was preliminary deoxidized in H 2 for over an hour at 1 873 K and was used in the following experiments. The slag was made by mixing the reagent grade of TiO 2 (purity Ͼ99 %), MgO (purity Ͼ99 %) and Al 2 O 3 (purity 99.6 %). The initial slag composition was set to the liquidus region in the TiO 2 -MgO-Al 2 O 3 phase diagram Fact Sage5. 4. 1. The calculated phase diagram for TiO 2 -MgO-Al 2 O 3 system at 1 973 K is described in Fig. 2. The initial slag composition is shown in Table 1 and is also plotted in Fig. 2.Sixteen gram of the deoxidized iron and the reagent grade of TiO 2 , MgO and Al 2 O 3 slag totally weighing 8 g were put in a magnesia or an alumina crucible, and the crucible was inserted in a carbon crucible with a carbon lid. The experiments were carried out by using a multipurpose electric resistance furnace, of which the heating element is carbon. After the sample was set in the furnace, the inner space of the furnace was decompressed to 8 Pa and was switched to an inert atmosphere by introducing an argon gas. By carrying out this operation repeatedly 2 time, the inside of the furnace was kept to be an argon gas atmosphere (0.011 to 0.013 MPa). Then, the sample was heated to 1 973 K according to the heat pattern shown in Fig. 3. The sample was equilibrated in the furnace by being held for 3 h in an argon atmosphere at 1 973 K. The sample was quickly cooled in the furnace by switching off the button of the power supply. After each experiment, metal and slag in the crucible were divided, and the Ti, Mg and Al contents of metal and slag and the O content of metal were analyzed by an inductively coupled plasma emission spectrometry (ICP) and an inert gas impulse infrared absorption spectroscopy, respectively.The compound in equilibrium with metal and slag was identified for each sample as follows: The...

Since cast titanium prostheses have many drawbacks, multi-directionally forged titanium grade 2 (MDF) was developed, and the application of the milling process was proposed for improving the titanium clasp. This in vitro study evaluated milled titanium clasps, including MDF titanium. Milling clasps were manufactured with commercially pure (CP) titanium grade 2 (CP 2), grade 4 (CP 4), Ti-6-Al-4V, and MDF. As a control, a CP 2 cast titanium clasp was fabricated in the conventional manner. No porosities and catastrophic failures were observed in the four milled titanium clasps. Fitness accuracy and retentive forces of milled CP 2 and CP 4 tended to be worse, and the milled MDF showed the higher retentive forces (12.45 N) than did cast and milled CP 2 clasps (9.32 N and 4.42 N). Milled titanium clasps can be recommended for longer-term clinical use as compared to cast clasps.