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1.
Microstructural investigation of Ti-Fe-Sn ultrafine eutectic composites reveals that β-Ti primary dendrite in eutectic matrix consists of TiFe and β-Ti for Ti 72Fe 22Sn 6 alloy. Similarly, the Ti 64Fe 32Sn 4 alloy and Ti 68Fe 23Sn 9 alloy consists of TiFe and Ti 3Sn micron-scale primary dendrites uniformly embedded in the TiFe and β-Ti eutectic structure. The β-Ti dendrite was formed in Ti 72Fe 22Sn 6 alloy, the large number of shear bands propagation and makes multiple steps on the fracture surface. The Ti 3Sn dendrite in Ti 68Fe 23Sn 9 ultrafine eutectic alloy leads slip bands which induce the work hardening that have important role in plasticity during deformation. On the other hand, TiFe dendrite in Ti 64Fe 32Sn 4 alloy was presented shear bands bypass and extinction while the propagation of shear bands. These microstructural changes lead to different deformation behavior in primary dendrite. Therefore, it is believed that the mechanical properties of Ti-Fe-Sn alloys could improve due to a different deformation behavior through the minute compositional tuning of Ti-Fe-Sn alloys. 相似文献
2.
High-strength nonequilibrium hypereutectic bulk alloys were obtained recently in the Ti–Fe and Ti–Fe–Co systems by arc-melting. Following these results, the influences of the additional alloying elements (V, Ni, Cu, Sn, B) on high strength hypereutectic Ti–Fe–Co bulk alloys are studied and analyzed in the present work. The structure of the hypereutectic quaternary Ti 67Fe 14Co 14Sn 5, Ti 67Fe 14Co 14V 5, Ti 70Fe 17Co 7Cu 6, Ti 70Fe 17Co 7Ni 6, and Ti 69.4Fe 14.8Co 14.8B 1 alloys obtained in the form of arc-melted ingots of about 20–30 mm diameter and 10–15 mm height was studied by X-ray diffractometry and scanning electron microscopy. The mechanical properties were tested by an Instron-type machine. Ti 67Fe 14Co 14Sn 5 alloy exhibits a high ultimate compressive strength of 1830 MPa and a large plastic strain of 24% which exceeds the ductility values obtained for Ti–Fe and Ti–Fe–Co alloys. The addition of Sn causes formation of a relatively rough eutectic structure which is preferable for the high strength hypereutectic alloys. Rough primary dendrites and eutectic rods of the cP2 intermetallic phase act as efficient barriers for shear strain and cracks propagation while fine eutectic rods of submicron size are quite effortlessly cut by deformation bands and cracks. 相似文献
3.
A series of (Ti 70.5Fe 29.5) 100−xSn x alloys with x=0, 1, 3, 5, 7 and 9 were fabricated by a suction casting into cylindrical rods with a 3 mm diameter and 50
mm length. Microstructural investigations of these alloys revealed that Sn addition was effective in modulating the phase
selection, length-scale of eutectic spacing and morphology of the colony in ultrafine eutectic structures upon solidification.
The spherical morphology of the ultrafine eutectic colony was effective in enhancing the plastic strain in the samples. On
theother hand, the formation of the bimodal eutectic structure stemming from a large temperature difference between two eutectic
temperatures had a strong influence on modulating the phase selection and length-scale of the ultrafine eutectic structures
and on controlling the strength and plastic strain of the ultrafine eutectic composites. 相似文献
4.
In this study, A series of the high strength (T 82Sn 18) 100-xNb x (x=0, 1, 3, 5, and 9 at%) ultrafine eutectic alloys with large plasticity are developed by suction casting method. The Ti 82Sn 18 binary eutectic alloy consists of a mixture of a hcp Ti 3Sn and a α-Ti phases having the plate-like lamellar type duplex structure with micro scaled eutectic colony. From the (T 82Sn 18) 97Nb 3, the alloy display structural heterogeneous distribution of ultrafine-scaled phases composed of β-Ti(Nb) solid solution surrounded by alternating plate-like shaped Ti 3Sn and α-Ti phases. With increasing Nb content, the volume fraction of β-Ti is continuously increased, which induced improving mechanical properties both strength and plasticity. Especially, (Ti 82Sn 18) 91Nb 9 alloy has the outstanding combination of the high strength ( σ y ≈1.1 GPa) and large plasticity ( ε p ≈36%) at room temperature. 相似文献
5.
Ti-based bulk metallic glass composite alloys Ti 56Zr 6Cu 19.8Pd 8.4Sn 1.8Nb 8, Ti 64Zr 4Cu 13.2Pd 5.6Sn 1.2Nb 12 and Ti 68Cu 13.2Pd 5.6Sn 1.2Nb 12 were designed to obtain the microstructure composing of β-Ti dendrites and glassy matrix. The compressive and three-point bending properties were investigated. It was found that the actual microstructure of the Nb-added alloys consisted of primarily precipitated β-Ti dendrites, network-like glassy matrix, and extra island-like Ti 2Cu intermetallic phase with different volume fractions. Under compressive loading, all the Nb-added alloys presented higher yield strength combined with remarkably increased plasticity. Under bending condition, however, the alloys Ti 56Zr 6Cu 19.8Pd 8.4Sn 1.8Nb 8 and Ti 64Zr 4Cu 13.2Pd 5.6Sn 1.2Nb 12 with higher Ti 2Cu volume fractions became completely brittle. The alloy Ti 68Cu 13.2Pd 5.6Sn 1.2Nb 12 could keep its plastic deformability due to the decreased Ti 2Cu volume fraction. Compressive deforming behavior of the Nb-added alloys was determined by the ductile β-Ti phase and glassy matrix, nevertheless, bending deforming behavior of the alloys was determined by the volume fraction and distribution of the brittle intermetallics. 相似文献
6.
Equilibrated Sn–Zn–Ti alloys and (Sn + Zn)/α-Ti diffusion couples have been studied by scanning electron microscopy, metallography, and differential scanning calorimetry. For the first time an isothermal section, at 600 °C, of the ternary Sn–Zn–Ti system has been constructed. A previously unknown ternary phase with approximate formula Ti 3Sn 2Zn 6 (probable homogeneity interval in the range Ti 5Sn 4Zn 11 to Ti 5Sn 3Zn 12) has been found.The solubility ranges of the titanium based solid solutions and the intermetallic phases have been looked for. As far as we could detect and in agreement with theoretical considerations, zinc dissolves more in Ti–Sn phases than tin into Ti–Zn compounds. Titanium additions of 3 and 4 at.% Ti do not influence significantly the Sn–Zn eutectic temperature. The experimentally determined melting enthalpies of the nearly eutectic alloys have values around 100 J g −1. 相似文献
7.
Microstructural investigations on ultrafine eutectic (Ti 65Fe 35) 100−xSn x alloys with x = 0, 1 and 3 at.% reveal that additional Sn is effective to control formation of the micron-scale dendrites and to decrease the length-scale of lamellar spacing with enhancing macroscopic plasticity at room temperature compression. Hence, it is possible to understand the influence of the microstructural change on the plasticity of the ultrafine eutectic Ti–Fe–Sn alloys. 相似文献
8.
Melt-spun ribbons and copper-mold cast cylinders of (Ti 0.5Cu 0.23Ni 0.2Sn 0.07) 100−xMo x bulk glass-forming alloys are prepared. Both Ti 50Cu 23Ni 20Sn 7 and (Ti 0.5Cu 0.23Ni 0.2Sn 0.07) 95Mo 5 melt-spun glassy ribbons exhibit large supercooled liquid regions, high reduced glass transition temperatures, and good thermal stabilities. During continuous heating of the melt-spun ribbons, both alloys present a two-stage crystallization behavior. Mo slightly lowers the glass-forming ability but significantly decreases the temperature of the second stage crystallization. For both alloys, the stable phases after heating are Ti 2Ni, TiCu, Ti 3Sn and β-(Cu,Sn). As-cast Ti 50Cu 23Ni 20Sn 7 cylinders contain dendritic hcp-Ti solid solution precipitates, as well as interdendritic glassy and Sn-rich crystalline phases. The ultimate compression stress reaches 2114 MPa with 5.5% plastic strain for 2-mm diameter cylinders. Yielding occurs at 1300 MPa, and Young’s modulus is 85.3 GPa. Mo improves and stabilizes the precipitation of a β-Ti solid solution but prevents glass formation in as-cast (Ti 0.5Cu 0.23Ni 0.2Sn 0.07) 95Mo 5 bulk alloys. The bulk samples contain dendritic β-Ti solid solution precipitates, Ti 2Ni particles and Sn-rich phases. The ultimate compression stress is 2246 MPa with about 1% plastic strain for a 3-mm diameter cylinder. σ0.2 is about 1920 MPa and Young’s modulus is 104 GPa. The high strength is attributed to both Mo solution strengthening and Ti 2Ni particle strengthening. The limited ductility is induced by the precipitation of brittle Ti 2Ni particles. 相似文献
9.
Three kinds of bulk-type ultrafine Ti x Sn y /TiNi (Ti x Sn y represents Ti 3Sn, Ti 2Sn, and Ti 5Sn 3 or Ti 6Sn 5) composites with homogeneous eutectic microstructure were prepared by arc melting. The composites exhibit high damping capacity (tan δ greater than 1 × 10 ?2) and enhanced mechanical strength (the highest fracture strength is 2.15 GPa). The damping capacity originates from TiNi and Ti 3Sn, while the eutectic contributes to the mechanical strength. 相似文献
10.
Large-scale Mg 90Cu 10 and Mg 90Cu 3Zn 7 nanostructure-dendrite composites were successfully fabricated using a water-cooled squeeze casting. The Mg 90Cu 3Zn 7 nanostructure-dendrite composite consisting of a mixture of hexagonal α-Mg and tetragonal MgCuZn phases has plasticity up
to 8.4 % in excess of that of the Mg 90Cu 10 nanostructure-dendrite composite consisting of a mixture of hexagonal α-Mg and orthorhombic Mg 2Cu phases. This implies that phase selection plays an important role in controlling the strength and plasticity of large-scale
Mg-based nanostructure-dendrite composites. 相似文献
11.
High-entropy alloys have been proved to be potential candidate materials in the biomedical field due to their balanced mechanical properties and excellent biocompatibility. The effects of atomic ratios on the as-cast microstructural evolution, mechanical properties, and electrochemical property of TiZrTaNbSn high-entropy alloys were studied systematically. The crystal structure of TiZrTaNbSn high-entropy alloys is single BCC phase, and the microstructural evolution is based on atomic ratio. The dendric structure, peritectic structure, pseudo eutectic and equiaxed grain, which are associated with element segregation, can be obtained by non-equal atomic ratio. Ti30Zr20Ta20Nb20Sn10 alloy demonstrates a high compressive strength and fracture strain, which are 2,571.8 MPa and 12%, respectively, and the fracture behavior is quasi-cleavage faults. The Ti45Z35Ta5Nb5Sn10, Ti30Zr20Ta20Nb20Sn10 and Ti35Zr25Ta15Nb15Sn10 alloys show excellent corrosion resistance according to Nyquist diagram, polarization curves and corrosion morphology. Compared with TiZrTaNbSn alloy, the corrosion rate of Ti45Zr35Ta5Nb5Sn10 alloy increases by about 98.9%. It can be concluded that non-equal atomic ratios are effective for microstructure control and performance optimization. 相似文献
12.
Three novel NiTiFeAlCu high-entropy alloys, which consist of nano-precipitates with face-centered cubic structure and matrix with body-centered cubic structure, were fabricated to investigate microstructures and mechanical properties. With the increase in Ni and Ti contents, the strength of NiTiFeAlCu alloy is enhanced, while the plasticity of NiTiFeAlCu alloy is lowered. Plenty of dislocations can be observed in the Ni 32Ti 32Fe 12Al 12Cu 12 high-entropy alloy. The size of nano-precipitates decreases with the increase in Ni and Ti contents, while lattice distortion becomes more and more severe with the increase in Ni and Ti contents. The existence of nano-precipitates, dislocations and lattice distortion is responsible for the increase in the strength of NiTiFeAlCu alloy, but it has an adverse influence on the plasticity of NiTiFeAlCu alloy. Ni 20Ti 20Fe 20Al 20Cu 20 alloy exhibits the substantial ability of plastic deformation and a characteristic of steady flow at 850 and 1000 °C. This phenomenon is attributed to a competition between the increase in the dislocation density induced by plastic strain and the decrease in the dislocation density due to the dynamic recrystallization. 相似文献
13.
对Mg-Zn-Y-Nd-Zr合金的显微组织和力学性能进行了研究。结果表明,Nd元素的加入部分取代了W相(Mg 3Zn 3Y 2)中的Y元素,形成了新的第二相Mg 3Zn 3(Y, Nd) 2。热挤压后观察到由细小的等轴再结晶晶粒和粗大的细长未再结晶晶粒组成的典型双峰结构。Nd元素的加入促进了热挤压过程中的动态再结晶,随着Nd含量的增加,动态再结晶率增加,挤压态合金的整体织构强度减弱。Nd的加入细化了晶粒并改善了合金的力学性能。添加0.5%(质量分数)Nd时,挤压态合金表现出高强度和高塑性的良好结合:屈服强度为362 MPa,极限抗拉伸强度为404 MPa,延伸率为10.2%。时效处理后合金的抗拉伸强度进一步提高,峰值时效极限抗拉伸强度可达421 MPa。合金的高强度主要归功于超细再结晶晶粒和析出强化。 相似文献
14.
The phase relationships of the Cu–Ti–Sn ternary system at 473 K have been investigated mainly by means of X-ray powder diffraction (XRD), scanning electron microscopy (SEM), optical microscopy (OM) and differential thermal analysis (DTA). The isothermal section consists of 17 single-phase regions, 33 two-phase regions and 17 three-phase regions. The existence of 12 binary compounds and 2 ternary compounds, namely Cu 4Ti, Cu 3Ti 2, Cu 4Ti 3, CuTi, CuTi 2, Cu 3Sn, Cu 6Sn 5, Ti 3Sn, Ti 2Sn, Ti 5Sn 3, Ti 6Sn 5, Ti 2Sn 3, CuTi 5Sn 3 and CuTiSn, are confirmed in the Cu–Ti–Sn ternary system at 473 K. No new ternary compound is found. The maximum solid solubility of Cu in Ti 6Sn 5 was approximately 10 at.% Cu. 相似文献
15.
Thermal spray assisted transient liquid phase (TLP) bonding of Ti−6Al−4V to Al2024 alloys was investigated, where the interlayer was 80 µm Babbitt thermal spray coat on Al substrate. Thermal spray creates a rough and clean surface which leads to establishing a joint with higher strength. The optimized parameters were bonding temperature of 580 °C and bonding time of 30 and 60 min. Microstructural observation together with XRD patterns confirmed the existence of Al 2Cu, Al 2CuMg, Cu 3Ti, TiAl 3, TiAl and Mg 2Sn intermetallic compounds formed in Al weld side. On the other hand, Ti 3Al, Sn 3Ti 5 and Ti 3Sn intermetallic compounds formed in Ti side. With increasing bonding time from 30 to 60 min, although the interlayer was not completely consumed, the thickness of remained Babbitt interlayer decreased to approximately 15 µm. The study showed that shear strength of the joint reaches the high value of 57 MPa obtained at larger bonding time of 60 min. 相似文献
16.
Ti-based Ti–Zr–Cu–Fe–Sn–Si bulk metallic glasses (BMGs) free from highly toxic elements Ni and Be were developed as promising biomaterials. The influence of (Ti + Zr)/Cu ratio on glass-formation, thermal stability, mechanical properties, bio-corrosion resistance, surface wettability and biocompatibility were investigated. In the present Ti-based BMG system, the Ti 47Zr 7.5Cu 40Fe 2.5Sn 2Si 1 glassy alloy exhibited the highest glass forming ability (GFA) corresponding to the largest supercooled liquid region, and a glassy rod with a critical diameter of 3 mm was prepared by copper-mold casting. The Ti-based BMGs possess high compressive strength of 2014–2185 MPa and microhardness of 606–613 Hv. Young's modulus of the Ti 47Zr 7.5Cu 40Fe 2.5Sn 2Si 1 glassy alloy was about 100 GPa, which is slightly lower than that of Ti–6Al–4V alloy. The Ti 47Zr 7.5Cu 40Fe 2.5Sn 2Si 1 glassy alloy with high GFA exhibited high bio-corrosion resistance, and good surface hydrophilia and cytocompatibility. The mechanisms for glass formation as well as the effect of (Ti + Zr)/Cu ratio on bio-corrosion behavior and biocompatibility are discussed. 相似文献
17.
From the perspective of biomechanics and forming technology, Ti−Fe−Zr−Sn−Y eutectic alloy was designed using a “cluster-plus-glue-atom” model, and then the alloy was prepared by laser additive manufacturing (LAM) on pure titanium substrate. The mechanical properties of the alloy were evaluated using micro-hardness and compression tester, and the elastic modulus was measured by nanoindenter. The results show that the alloy exhibits a high hardness of HV (788±10), a high strength of 2229 MPa, a failure strain of 14%, and a low elastic modulus of 87.5 GPa. The alloy also has good tribological, chemical, forming, and biological properties. The comprehensive performances of the Ti 64.51Fe 26.40Zr 5.86Sn 2.93Y 0.30 alloy are superior to those of the Ti 70.5Fe 29.5 eutectic alloy and commercial Ti−6Al−4V alloy. All the above-mentioned qualities make the alloy a promising candidate as LAM biomaterial. 相似文献
18.
A variety of lead-free solder alloys were studied for use as flip-chip interconnects including Sn-3.5Ag, Sn-0.7Cu, Sn-3.8Ag-0.7Cu,
and eutectic Sn-37Pb as a baseline. The reaction behavior and reliability of these solders were determined in a flip-chip
configuration using a variety of under-bump metallurgies (TiW/Cu, electrolytic nickel, and electroless Ni-P/Au). The solder
micro-structure and intermetallic reaction products and kinetics were determined. The Sn-0.7Cu solder has a large grain structure
and the Sn-3.5Ag and Sn-3.8Ag-0.7Cu have a fine lamellar two-phase structure of tin and Ag 3Sn. The intermetallic compounds were similar for all the lead-free alloys. On Ni, Ni 3Sn 4 formed and on copper, Cu 6Sn 5Cu 3Sn formed. During reflow, the intermetallic growth rate was faster for the lead-free alloys, compared to eutectic tin-lead.
In solidstate aging, however, the interfacial intermetallic compounds grew faster with the tinlead solder than for the lead-free
alloys. The reliability tests performed included shear strength and thermomechanical fatigue. The lower strength Sn-0.7Cu
alloy also had the best thermomechanical fatigue behavior. Failures occurred near the solder/intermetallic interface for all
the alloys except Sn-0.7Cu, which deformed by grain sliding and failed in the center of the joint. Based on this study, the
optimal solder alloy for flip-chip applications is identified as eutectic Sn-0.7Cu.
Editor’s Note: A hypertext-enhanced version of this article can be found at www.tms.org/pubs/journals/JOM/0106/Frear-0106.html
For more information, contact D.R. Frear, Interconnect Systems Laboratories, Motorola, Tempe, AZ 85284; (480) 413-6655; fax
(480) 413-4511; e-mail darrel.frear@motorola.com. 相似文献
19.
Cu 6Sn 5 exists at least in two crystal structures with an allotropic transformation from monoclinic η'-Cu 6Sn 5 at temperatures lower than 186 °C to hexagonal η-Cu 6Sn 5. We recently discovered that the hexagonal structure of Cu 6Sn 5 in lead-free solder alloys with trace Ni additions is stable down to room temperature using high resolution TEM/ED/EDS. This report further confirm the phase stabilising effect of Ni by analysing samples of Cu 6Sn 5 extracted from a Sn-0.7wt%Cu-0.05wt%Ni lead-free solder alloy. Techniques used include X-ray diffraction, transmission electron microscopy and differential scanning calorimetry. 相似文献
20.
A systematic study of the solidification mechanisms of binary Sn-Cu and ternary Sn-Cu-Ni alloys has been carried out. It is
found that Sn-Cu is a weakly-irregular eutectic system with Cu 6Sn 5 as the leading phase. Interestingly, two different eutectic morphologies (coarse and fine) are found to grow simultaneously
during eutectic solidification. When the growth rate or composition is changed, the eutectic interface breaks down into a
cellular eutectic with the fine eutectic in the center of the cells and the coarse one at the cell boundaries. The mechanisms
responsible for these phenomena are discussed in conjunction with the beneficial effect of Ni additions to the Sn-Cu solder. 相似文献
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