scholarly journals Microstructure and mechanical properties of Ti-Ti2AlNb interface

2021 ◽  
Vol 30 ◽  
pp. 2633366X2092971
Author(s):  
Tao Niu ◽  
Bo Jiang ◽  
Ning Zhang ◽  
Yaoqi Wang

Diffusion bonding of Ti2AlNb alloy using pure titanium (Ti) foil as an interlayer was carried out on superplastic forming and diffusion bonding special equipment by gas pressure loading method. The microstructure of Ti-Ti2AlNb interface was observed using scanning electron microscope and energy-dispersive spectrometer while the mechanical properties of the joints were evaluated by shear test. The results show that the thickness of Ti foil interlayer has a great influence on the microstructure and shear strength of the interface diffusion region. When the thickness of the intermediate layer is thin (25 µm), Ti, aluminum (Al), and niobium (Nb) elements are fully diffused with uniform element distribution through the diffusion region. The diffusion layer region presents uniform, fine, and disordered lamellar α-Ti + β-Ti dual-phase structure with high shear strength. When the thickness of Ti foil interlayer is thick (50 µm), the distribution of Al elements is relatively uniform through the diffusion region due to its smaller radius and faster diffusion speed, and Ti and Nb elements present gradient distribution from the middle to both sides. The diffusion layer region presents a coarse and long strip shape α-Ti + β-Ti dual-phase structure in the middle part and a fine needle-like or irregular α-Ti + β-Ti dual-phase structure in both side parts, with slightly lower shear strength. Temperature has a great influence on the microstructure and mechanical properties of the diffusion bonding joints. The diffusion region presents a black α-Ti strip area in the middle part with the width of about 10 µm at lower temperature (910°C) with poorer property, due to the grain growth of the parent metal, the property is slightly poorer when the temperature is too high (960°C), and the optimal temperature is 930°C with a higher shear strength.

2021 ◽  
Author(s):  
Gamri Hamza ◽  
Allaoui Omar ◽  
Zidelmel Sami

Abstract The effect of the morphology and the martensite volume fraction on the microhardness, the tensile, the friction and the wear behavior of API X52 dual phase (DP) steel has been investigated. Three different heat treatments were used to develop dual phase steel with different morphologies and with different amounts of martensite: Intermediate Quenching Treatment/Water (IQ); Step Quenching Treatment (SQ) and direct quenching (DQ). Tribological tests are conducted on DP steels using a ball-on-disc configuration under normal load of 5 N and at a sliding speed of 4 cm/s were used to study the friction and wear behavior of treated samples. Results show that the ferrite–martensite morphology has a great influence on the mechanical properties of dual phase steel. The steel subjected to (IQ) treatment attain superior mechanical properties compared to the SQ and the DQ treatments. On the other hand, it is also found that the friction coefficient and the wear rate (volume loss) decrease when the hardness and the martensite volume fraction increase. The steel with fine fibrous martensite provide good wear resistance.


Metals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 94
Author(s):  
Yuqing Chen ◽  
Guofeng Wang ◽  
Yongkang Liu ◽  
Liqiang Zhan ◽  
He Diao ◽  
...  

Titanium alloys used to be welded to gain good joint strength at 920 °C through diffusion bonding. However, due to the heat preservation at high temperatures for a long time, we obtain joints with great bond strength while the mechanical properties of the sheet are lost. In this paper, taking Ti6Al4V alloy as an example, we studied the microstructure of the surface under the different times of surface mechanical attrition treatment (SMAT). In addition, the microstructure and mechanical properties after diffusion bonding at 800 °C-5 MPa-1 h were also conducted. The results show that the shear strength of TC4 alloy welded joint after SMAT treatment is improved, and the maximum shear strength can reach 797.7 MPa, up about 32.4%


Author(s):  
Nader Nadermanesh ◽  
Abdolhamid Azizi ◽  
Sahebali Manafi

The diffusion bonding of 7075, 6061 and 5083 aluminium alloys to AZ31B magnesium was investigated using copper interlayer. An optical microscope along with scanning electron microscopes, equipped with an energy dispersive spectrometry/electron probe microanalysis, was utilized to characterize the microstructure of the joint. The mechanical properties of the joint were also assessed by micro-hardness and shear strength tests. The results indicate the high effect of temperature on the bonding results; so that, with a small change in temperature, severe changes were observed in the bonding results. A temperature range of 475°C–485°C and a minimum duration of 30 min with a low bonding pressure of 0.4 MPa were identified as advisable process conditions. The joint evaluation revealed the formation of CuAl2, Cu9Al4 and Al-Mg-Cu ternary phases on the aluminium-copper side, as well as Cu2Mg, CuMg2 and Al-Mg-Cu ternary phases on the magnesium-copper side in the reaction layer. When increasing the bonding temperature and duration, the amount of intermetallic compounds and, as a result, the mechanical properties of the joints changed. The highest shear strength and micro-hardness, related to the bonding performed at 480°C and holding time of 45 min, were 31.03 MPa and 167 HV, respectively.


Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1437
Author(s):  
Zeming Wang ◽  
Xu Yang ◽  
Jing Wang ◽  
Zhonglin Xiao ◽  
Fugong Qi ◽  
...  

The development of welding technology for zirconium alloy has great significance on the safety, stability, and reliability of the operation of the nuclear reactor. In this work, vacuum diffusion bonding of Zr-4 alloy was studied at the diffusion temperature ranging from 760 to 820 °C with holding times of 30–90 min. The effects of diffusion bonding temperature and holding time on the interfacial microstructure and mechanical properties of the diffusion bonded Zr-4 alloy joints were investigated in detail, and the relationship between the interfacial microstructure and shear strength of the diffusion bonded joints was discussed. The results show that the interface bonding ratio of the diffusion bonded Zr-4 joint gradually increased from 74% to 95% with the increasing of bonding temperature. In addition, the grain size of the base material became a larger and brittle second phase composed of Zr(Cr, Fe)2 and eutectic α-Zr + Zr(Fe, Cr)2 formed in the joint with the increase of the temperature as well as the extension of the bonding time. The highest shear strength of 349 MPa was obtained at 800 °C for 30 min under 7 MPa, and the crack of the joint was primarily propagated along with the base material rather than the bonded interface.


2011 ◽  
Vol 194-196 ◽  
pp. 89-94
Author(s):  
An Ming Li ◽  
Meng Juan Hu

The influence of sub-temperature quenching temperature on the strength and hardness of 65Mn steel during austenite inverse phase transformation is studied and the microstructure and property are analyzed. The results showed that in the range of 760~810°C , the strength and hardness of the 65Mn steel second sub-temperature quenched increased with quenching temperature increasing, reached the highest strength and hardness at 790°C quenching and then began to decrease. A small number of ferrite and ferrite dual-phase structure existed in martensite when quenching temperature was low. Fine martensite was obtained by second sub-temperature quenching due to the smaller austenitic crystal grain and austenitic nucleation sites. The mechanical properties of samples second sub-temperature quenched are better than that of conventional samples 830°C once quenched.


Author(s):  
L.J. Chen ◽  
H.C. Cheng ◽  
J.R. Gong ◽  
J.G. Yang

For fuel savings as well as energy and resource requirement, high strength low alloy steels (HSLA) are of particular interest to automobile industry because of the potential weight reduction which can be achieved by using thinner section of these steels to carry the same load and thus to improve the fuel mileage. Dual phase treatment has been utilized to obtain superior strength and ductility combinations compared to the HSLA of identical composition. Recently, cooling rate following heat treatment was found to be important to the tensile properties of the dual phase steels. In this paper, we report the results of the investigation of cooling rate on the microstructures and mechanical properties of several vanadium HSLA steels.The steels with composition (in weight percent) listed below were supplied by China Steel Corporation: 1. low V steel (0.11C, 0.65Si, 1.63Mn, 0.015P, 0.008S, 0.084Aℓ, 0.004V), 2. 0.059V steel (0.13C, 0.62S1, 1.59Mn, 0.012P, 0.008S, 0.065Aℓ, 0.059V), 3. 0.10V steel (0.11C, 0.58Si, 1.58Mn, 0.017P, 0.008S, 0.068Aℓ, 0.10V).


Alloy Digest ◽  
1962 ◽  
Vol 11 (3) ◽  

Abstract ALUMINUM 220 is a 10% magnesium-aluminum casting alloy having the highest combination of mechanical properties, corrosion resistance and machinability. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive and shear strength as well as fatigue. It also includes information on high temperature performance and corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Al-112. Producer or source: Aluminum Company of America.


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