Effects of Mo Addition on Deformation Behavior of Metastable Beta-Type Ti-Mn Single Crystals

2018 ◽  
Vol 941 ◽  
pp. 1360-1365 ◽  
Author(s):  
Ryota Morioka ◽  
Ken Cho ◽  
Hiroyuki Y. Yasuda

In this study, to clarify the effects of Mo addition on deformation behavior of Ti-Mn alloys, the mechanical properties and the deformation structures of the alloys were investigated using Ti-Mn and Ti-Mn-Mo alloys polycrystals and single crystals. We found that the elongation of Ti-Mn alloys are improved from approximately 5% to 30% by Mo addition, with maintaining ultimate tensile strength of 900 MPa. The excellent strength-ductility balance of Ti-Mn-Mo alloys is caused by {332}<113> twinning, which is unique twinning for metastable β-type titanium alloys. Additionally, the deformation behavior of Ti-Mn and Ti-Mn-Mo alloys was investigated in detail by using single crystals focusing on a critical resolved shear stress (CRSS). As a result, we found for the first time that CRSS for {332}<113> twinning in Ti-Mn-Mo alloy was lower than that in Ti-Mn alloy. Moreover, in Ti-Mn-Mo alloy, CRSS for {332}<113> twinning was lower than that for {112}<111> slip. These results suggest that CRSS for {332}<113> twinning in Ti-Mn alloys is decreased by Mo addition.

2020 ◽  
Vol 321 ◽  
pp. 05001
Author(s):  
K. Cho ◽  
R. Morioka ◽  
H.Y. Yasuda

The influences of Mo addition on the tensile properties and deformation behavior of β-type Ti-Mn alloys were investigated with particular focus on {332}<113> deformation twinning. We found that Ti-7Mn and Ti-5Mo-3Mo alloys exhibit completely different tensile properties, despite having the same microstructure and stability of the β phase. The Ti-5Mn-3Mo alloy demonstrates higher tensile strength and larger ductility than the Ti-7Mn alloy due to its strong work hardening, caused by {332} <113> deformation twinning. The critical resolved shear stress (CRSS) for {332}<113> deformation twinning in these alloys was measured by compression tests using single crystals. It was thereby found that Mo addition is effective in decreasing the CRSS for {332}<113> deformation twinning in Ti-Mn alloys.


2019 ◽  
Vol 25 (2) ◽  
pp. 427-432 ◽  
Author(s):  
Benjamin Himmel ◽  
Dominik Rumschoettel ◽  
Wolfram Volk

Purpose Directly printing molten metal droplets on a build platform to create full dense metal parts is a promising additive manufacturing process. This study aims of to analyse the effects of the thermal conditions on the resulting tensile properties of parts made from aluminium 4047A built in droplet-based metal printing. Design/methodology/approach A drop-on-demand print head with pneumatic actuation is used to eject droplets on a nickel sheet mounted on the heated build platform. Tensile specimens are machined from cuboid blocks built by successive droplet deposition and tested in a universal testing machine. The ultimate tensile strength, uniform elongation and yield strength are evaluated and presented. Micro-sections are taken from the printed blocks to examine the internal pores and the metal’s microstructure. Findings With an increase in the interface temperature the uniform elongation increases from 0.5 to 12%, while the yield strength decreases from 130 to 90 MPa. The ultimate tensile strength increases from 130 MPa to a maximum of 190 MPa at an interface temperature of 530º C and slightly falls for higher interface temperatures. Those values are in the same range as conventionally casted parts of the same alloy. The authors’ hypothesis is that the main effect responsible for the mechanical properties is the wetting of solid material by the liquid droplet and not remelting, as has been reported in literature. Originality/value To the best of the authors’ knowledge, this is the first time that mechanical properties of aluminium 4047A built by a droplet-based additive manufacturing process are published for different interface temperatures. It is also the first time that the main effect on mechanical properties is attributed to wetting instead of remelting.


1967 ◽  
Vol 45 (2) ◽  
pp. 1063-1074 ◽  
Author(s):  
D. F. Stein

Molybdenum single crystals containing less than 10 p.p.m. of carbon, 5 p.p.m. of nitrogen, and 5 p.p.m. of oxygen have been prepared by zone melting and hydrogen gas purification. The mechanical properties of the crystals have been measured in tension and compression over a range of temperature from 20 to 298 °K. It was found that the critical resolved shear stress and the temperature dependence of the critical resolved shear stress decreased with increasing purity. It was found that at all test temperatures the CRSS law fails. The critical resolved shear stress is a minimum in the (100) tension axis orientation and reaches a maximum with the tensile axis along the (110)(111) line of the stereographic triangle. It was also found that the ductility of molybdenum single crystals was not improved by purification.


RSC Advances ◽  
2021 ◽  
Vol 11 (38) ◽  
pp. 23719-23724
Author(s):  
Md. Lokman Ali

The effect of transition-metals (TM) addition on the mechanical properties of CrCoNi medium entropy alloys (MEAs) was investigated.


2020 ◽  
Vol 17 (6) ◽  
pp. 831-836
Author(s):  
M. Vykunta Rao ◽  
Srinivasa Rao P. ◽  
B. Surendra Babu

Purpose Vibratory weld conditioning parameters have a great influence on the improvement of mechanical properties of weld connections. The purpose of this paper is to understand the influence of vibratory weld conditioning on the mechanical and microstructural characterization of aluminum 5052 alloy weldments. An attempt is made to understand the effect of the vibratory tungsten inert gas (TIG) welding process parameters on the hardness, ultimate tensile strength and microstructure of Al 5052-H32 alloy weldments. Design/methodology/approach Aluminum 5052 H32 specimens are welded at different combinations of vibromotor voltage inputs and time of vibrations. Voltage input is varied from 50 to 230 V at an interval of 10 V. At each voltage input to the vibromotor, there are three levels of time of vibration, i.e. 80, 90 and 100 s. The vibratory TIG-welded specimens are tested for their mechanical and microstructural properties. Findings The results indicate that the mechanical properties of aluminum alloy weld connections improved by increasing voltage input up to 160 V. Also, it has been observed that by increasing vibromotor voltage input beyond 160 V, mechanical properties were reduced significantly. It is also found that vibration time has less influence on the mechanical properties of weld connections. Improvement in hardness and ultimate tensile strength of vibratory welded joints is 16 and 14%, respectively, when compared without vibration, i.e. normal weld conditions. Average grain size is measured as per ASTM E 112–96. Average grain size is in the case of 0, 120, 160 and 230 is 20.709, 17.99, 16.57 and 20.8086 µm, respectively. Originality/value Novel vibratory TIG welded joints are prepared. Mechanical and micro-structural properties are tested.


Metals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 31
Author(s):  
Hongxin Liao ◽  
Taekyung Lee ◽  
Jiangfeng Song ◽  
Jonghyun Kim ◽  
Fusheng Pan

The microstructures and mechanical properties of the Mg88.5Zn5Y6.5-XREX (RE = Yb and Ce, X = 0, 1.5, 3.0, and 4.5) (wt.%) alloys were investigated in the present study. Mg88.5Zn5Y6.5 is composed of three phases, namely, α-Mg, long-period stacking ordered (LPSO) phases, and intermetallic compounds. The content of the LPSO phases decreased with the addition of Ce and Yb, and no LPSO phases were detected in Mg88.5Zn5Y2.0Yb4.5. The alloys containing the LPSO phases possessed a stratified microstructure and exhibited excellent mechanical properties. Mg88.5Zn5Y5.0Ce1.5 exhibited the highest creep resistance and mechanical strength at both room temperature and 200 °C, owing to its suitable microstructure and high thermal stability. The yield strength of Mg88.5Zn5Y5.0Ce1.5 at room temperature was 358 MPa. The ultimate tensile strength of Mg88.5Zn5Y5.0Ce1.5 at room temperature and 200 °C was 453 MPa and 360 MPa, respectively.


Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 109
Author(s):  
Ateekh Ur Rehman ◽  
Nagumothu Kishore Babu ◽  
Mahesh Kumar Talari ◽  
Yusuf Siraj Usmani ◽  
Hisham Al-Khalefah

In the present study, a friction welding process was adopted to join dissimilar alloys of Ti-Al-4V to Nitinol. The effect of friction welding on the evolution of welded macro and microstructures and their hardnesses and tensile properties were studied and discussed in detail. The macrostructure of Ti-6Al-4V and Nitinol dissimilar joints revealed flash formation on the Ti-6Al-4V side due to a reduction in flow stress at high temperatures during friction welding. The optical microstructures revealed fine grains near the Ti-6Al-4V interface due to dynamic recrystallization and strain hardening effects. In contrast, the area nearer to the nitinol interface did not show any grain refinement. This study reveals that the formation of an intermetallic compound (Ti2Ni) at the weld interface resulted in poor ultimate tensile strength (UTS) and elongation values. All tensile specimens failed at the weld interface due to the formation of intermetallic compounds.


Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 94
Author(s):  
Petar Janjatovic ◽  
Olivera Eric Cekic ◽  
Leposava Sidjanin ◽  
Sebastian Balos ◽  
Miroslav Dramicanin ◽  
...  

Austempered ductile iron (ADI) is an advanced cast iron material that has a broad field of application and, among others, it is used in contact and for conveyance of fluids. However, it is noticed that in contact with some fluids, especially water, ADI material becomes brittle. The most significant decrease is established for the elongation. However, the influence of water and the cause of this phenomenon is still not fully understood. For that reason, in this paper, the influence of different water concentrations in ethyl alcohol on the mechanical properties of ADI materials was studied. The test was performed on two different types of ADI materials in 0.2, 4, 10, and 100 vol.% water concentration environments, and in dry condition. It was found that even the smallest concentration of water (0.2 vol.%) causes formation of the embrittled zone at fracture surface. However, not all mechanical properties were affected equally and not all water concentrations have been critical. The highest deterioration was established in the elongation, followed by the ultimate tensile strength, while the proof strength was affected least.


Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 647 ◽  
Author(s):  
Bingrong Zhang ◽  
Lingkun Zhang ◽  
Zhiming Wang ◽  
Anjiang Gao

In order to obtain high-strength and high-ductility Al–Si–Cu–Mg alloys, the present research is focused on optimizing the composition of soluble phases, the structure and morphology of insoluble phases, and artificial ageing processes. The results show that the best matches, 0.4 wt% Mg and 1.2 wt% Cu in the Al–9Si alloy, avoided the toxic effect of the blocky Al2Cu on the mechanical properties of the alloy. The addition of 0.6 wt% Zn modified the morphology of eutectic Si from coarse particles to fine fibrous particles and the texture of Fe-rich phases from acicular β-Fe to blocky π-Fe in the Al–9Si–1.2Cu–0.4Mg-based alloy. With the optimization of the heat treatment parameters, the spherical eutectic Si and the fully fused β-Fe dramatically improved the ultimate tensile strength and elongation to fracture. Compared with the Al–9Si–1.2Cu–0.4Mg-based alloy, the 0.6 wt% Zn modified alloy not only increased the ultimate tensile strength and elongation to fracture of peak ageing but also reduced the time of peak ageing. The following improved combination of higher tensile strength and higher elongation was achieved for 0.6 wt% Zn modified alloy by double-stage ageing: 100 °C × 3 h + 180 °C × 7 h, with mechanical properties of ultimate tensile strength (UTS) of ~371 MPa, yield strength (YS) of ~291 MPa, and elongation to fracture (E%) of ~5.6%.


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