Photoinduced reactivity of titanium dioxide

Physical metallurgy of Ti–Ni-based shape memory alloys

Magnesium alloys have received an increasing interest in the past 12 years for potential applications in the automotive, aircraft, aerospace, and electronic industries. Many of these alloys are strong because of solid-state precipitates that are produced by an age-hardening process. Although some strength improvements of existing magnesium alloys have been made and some novel alloys with improved strength have been developed, the strength level that has been achieved so far is still substantially lower than that obtained in counterpart aluminum alloys. Further improvements in the alloy strength require a better understanding of the structure, morphology, orientation of precipitates, effects of precipitate morphology, and orientation on the strengthening and microstructural factors that are important in controlling the nucleation and growth of these precipitates. In this review, precipitation in most precipitation-hardenable magnesium alloys is reviewed, and its relationship with strengthening is examined. It is demonstrated that the precipitation phenomena in these alloys, especially in the very early stage of the precipitation process, are still far from being well understood, and many fundamental issues remain unsolved even after some extensive and concerted efforts made in the past 12 years. The challenges associated with precipitation hardening and age hardening are identified and discussed, and guidelines are outlined for the rational design and development of higher strength, and ultimately ultrahigh strength, magnesium alloys via precipitation hardening.

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Precipitation and Hardening in Magnesium Alloys

https://www.tpbin.com/Uploads/Subjects/643149a0-8194-4c67-bf05-73fae6f0d14f.pdf

Development of new metallic alloys for biomedical applications

Catalytic Enantioselective Addition of Allylic Organometallic Reagents to Aldehydes and Ketones

Metallographic studies have been made of precipitation processes in Ti-50 pct Ni and Ti-52 pct Ni (at. pct) shape memory alloys. The eutectoid and peritectoid reactions previously reported for near-equiatomic and Ni-rich TiNi alloys were not observed for either composition. In the Ti-52Ni alloy, diffusional transformations take place, similar to those in supersaturated alloys. The precipitation sequence can be written asβ
 0 → Ti11Ni14 → Ti2Ni3 → TiNi3. The solidus line of the TiNi phase in the Ti-52Ni alloy lies at 812 ± 22 °C. Morphological characteristics of the various precipitate phases are described in detail.

Precipitation processes in near-equiatomic TiNi shape memory alloys

The long-period stacking order (LPSO) structures in rapidly solidified Mg97Zn1Y2 alloy have been studied by conventional and high-resolution transmission electron microscopes (HRTEMs). There are four kinds of stacking sequences in the LPSO structures, i.e., 18R of ABABABCACACABCBCBC, 14H of ACBCBABABABCBC, 10H of ABACBCBCAB and 24R of ABABABABCACACACABCBCBCBC. The 18R structure is dominantly observed in the present study. The rest three are occasionally observed in places. The 10H and 24R structures are recently discovered. The lattice constants of 18R( 1 1 ¯ 1 1 ¯ 2 )3, 14H( 2 ¯ 1 2 ¯ 1 1 ¯ 1 1 ¯ 2 1 ¯ 2 ), 10H( 1 3 ¯ 1 1 ¯ 3 1 ¯ ) and 24R( 1 1 ¯ 1 1 ¯ 1 1 ¯ 2 )3 structures are estimated to be a = 0.320 nm and c = 4.678 nm, a = 0.325 nm and c = 3.694 nm, a = 0.325 nm and c = 2.603 nm, a = 0.322 nm and c = 6.181 nm for the hexagonal structure, respectively.

Variation of long-period stacking order structures in rapidly solidified Mg97Zn1Y2 alloy

All-round shape memory effect in Ni-rich TiNi alloys generated by constrained aging

Interaction between long period stacking order (LPSO) phase and { 1 0 1 ¯ 2 } deformation twin in rapidly solidified Mg97Zn1Y2 alloy is investigated. The densely developed LPSO phase prevents the growth of { 1 0 1 ¯ 2 } deformation twin in Mg matrix. On the other hand, the LPSO phase with low density cannot be the resistance of the twinning. The trace of basal plane in such LPSO phase deviates with constant angle of about 3.8° at the twin boundary. This angle is well explained by the atomic movement with shuffling in the formation of { 1 0 1 ¯ 2 } twin. The interfacial microstructure of { 1 0 1 ¯ 2 } deformation twin is also discussed on the basis of high resolution electron microscopy (HREM).

Interaction between long period stacking order phase and deformation twin in rapidly solidified Mg97Zn1Y2 alloy

Ti-Mo (mol%) Ti-Mo-Ag (mol%) Ti-Mo-Sn (mol%) Ti-5.0Mo + Ti-5.0Mo-0.5Ag + Ti-5.0Mo-1.0Sn + Ti-6.0Mo + Ti-5.0Mo-1.0Ag + Ti-5.0Mo-2.0Sn + Ti-5.0Mo-2.0Ag + Ti-5.0Mo-3.0Sn + Ti-5.0Mo-3.0Ag + Ti-5.0Mo-4.0Sn + Ti-5.0Mo-4.0Ag + Ti-5.0Mo-5.0Sn + Ti-5.0Mo-5.0Ag + Ti-6.0Mo-1.0Sn + Ti-6.0Mo-1.0Ag + Ti-6.0Mo-2.0Sn + Ti-6.0Mo-2.0Ag + Ti-6.0Mo-3.0Sn + Ti-6.0Mo-3.0Ag + Ti-6.0Mo-4.0Sn Ti-6.0Mo-4.0Ag + Ti-6.0Mo-5.0Sn

/pdf/shape-memory-properties-of-biomedical-ti-mo-ag-and-ti-mo-sn-4lb28kptp0.pdf

Minoru Nishida

Papers

Precipitation processes in near-equiatomic TiNi shape memory alloys

Variation of long-period stacking order structures in rapidly solidified Mg97Zn1Y2 alloy

All-round shape memory effect in Ni-rich TiNi alloys generated by constrained aging

Interaction between long period stacking order phase and deformation twin in rapidly solidified Mg97Zn1Y2 alloy

Shape Memory Properties of Biomedical Ti-Mo-Ag and Ti-Mo-Sn Alloys