The Influence of Aging Treatments on the Notched Tensile Strength of Ti-6Al-6V-2Sn Laser Welds

2008 ◽  
Vol 47-50 ◽  
pp. 185-188
Author(s):  
Lv Wen Tsay ◽  
C.X. Lee ◽  
W.C. Chung ◽  
C. Chen
Keyword(s):  
Tensile Strength ◽  
Crack Growth ◽  
High Hardness ◽  
Tensile Tests ◽  
Growth Direction ◽  
Laser Welds ◽  
Different Temperatures ◽  
Crack Growth Direction ◽  
Notched Tensile Strength ◽  
Fracture Features

Notched tensile tests were performed to evaluate the presence of notch on the tensile strength of Ti-6Al-6V-2Sn laser welds, which were post-weld aged at different temperatures. Ti-6Al-6V-2Sn laser welds showed notch brittleness except for the welds aged at/above 704 oC. Fine acicular α uniformly distributed in β matrix in the fusion zone accounted for the high hardness (Hv 440) as compared with mill-annealed base metal. Overaging at/above 704 oC resulted in coarsening the microstructures and decreased notch brittleness. The fracture features of the weld were strongly affected by the orientation of the solidified structures with respect to the crack growth direction.

Studies of Ti-15V-3Cr-3Al-3Sn after Thermohydrogen Processing

2012 ◽  
Vol 476-478 ◽  
pp. 2440-2443
Author(s):  
Rong Tan Huang ◽  
Pei Chiao Tsay ◽  
Wen Han Chen
Keyword(s):  
Tensile Strength ◽  
Tensile Test ◽  
Room Temperature ◽  
High Hardness ◽  
Microstructure Modification ◽  
Β Phase ◽  
Notched Tensile Strength ◽  
Thermohydrogen Processing ◽  
The Relationship ◽  
Fracture Features

Ti-15V-3Cr-3Al-3Sn, β-phase titanium alloy, is subjected to study the microstructure and mechanical behavior after thermohydrogen processing. It aims to study the relationship between microstructure modification and notched tensile test at room temperature. Meanwhile, the notched tensile test and fracture features of Ti-15-3 alloy without THP is also discussed. It follows that the hardness of Ti-15V-3Cr-3Al-3Sn would be clearly enhaced up to Hv 499 after thermohydrogen processing due to grain refinement. Besides, the notched tensile strength of the as-received specimen is about 904 MPa, and is increased to 959 MPa after THP, that is, Ti-15-3 alloy after THP shows higher hardness and notched tensile strength than as-received alloy. The enhanced high hardness does not induce a significant notched embrittlement effect.

scholarly journals Microstructural Characterization of Laser Weld of Hot-Stamped Al-Si Coated 22MnB5 and Modification of Weld Properties by Hybrid Welding

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3943
Author(s):  
Hana Šebestová ◽  
Petr Horník ◽  
Šárka Mikmeková ◽  
Libor Mrňa ◽  
Pavel Doležal ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Fusion Zone ◽  
Microstructural Characterization ◽  
Tensile Tests ◽  
Laser Weld ◽  
Martensitic Microstructure ◽  
Laser Welds ◽  
Weld Properties ◽  
Weld Fusion Zone

The presence of Al-Si coating on 22MnB5 leads to the formation of large ferritic bands in the dominantly martensitic microstructure of butt laser welds. Rapid cooling of laser weld metal is responsible for insufficient diffusion of coating elements into the steel and incomplete homogenization of weld fusion zone. The Al-rich regions promote the formation of ferritic solid solution. Soft ferritic bands cause weld joint weakening. Laser welds reached only 64% of base metal's ultimate tensile strength, and they always fractured in the fusion zone during the tensile tests. We implemented hybrid laser-TIG welding technology to reduce weld cooling rate by the addition of heat of the arc. The effect of arc current on weld microstructure and mechanical properties was investigated. Thanks to the slower cooling, the large ferritic bands were eliminated. The hybrid welds reached greater ultimate tensile strength compared to laser welds. The location of the fracture moved from the fusion zone to a tempered heat-affected zone characterized by a drop in microhardness. The minimum of microhardness was independent of heat input in this region.

Study on Ductile Fracture Including Shear-Lip Fracture under Mixed Mode Loading Condition

2008 ◽  
Vol 33-37 ◽  
pp. 23-28
Author(s):  
Masanori Kikuchi ◽  
Shougo Sannoumaru
Keyword(s):  
Numerical Simulation ◽  
Crack Growth ◽  
Fracture Zone ◽  
Mixed Mode ◽  
Loading Condition ◽  
Growth Direction ◽  
Dimple Fracture ◽  
Shear Lip ◽  
Crack Growth Direction ◽  
Fracture Tests

Dimple fracture tests are conducted under mode I and mixed mode lading conditions. Dimple fracture zone and shear-lip fracture zone are observed by scanning electron microscope precisely. It is found that crack growth direction is affected largely by the change of loading condition. It is also found that the differences of fracture pattern between mid-plane and at free surface are very large. Void diameter and crack growth direction are measured. Numerical simulation is conducted to simulate fracture tests in three-dimensional field. Gurson’s constitutive equation is used and large deformation analyses are conducted. It is assumed that void nucleation is controlled by both plastic strain and stress. Numerical results are compared with those of experiments. It is found that results of numerical simulation agree well with those of experiment qualitatively.

scholarly journals Effects of Different Solid Solution Temperatures on Microstructure and Mechanical Properties of the AA7075 Alloy After T6 Heat Treatment

2019 ◽  
Vol 38 (2019) ◽  
pp. 892-896 ◽  
Author(s):  
Süleyman Tekeli ◽  
Ijlal Simsek ◽  
Dogan Simsek ◽  
Dursun Ozyurek
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Solid Solution ◽  
Tensile Strength ◽  
Tensile Tests ◽  
Solution Temperature ◽  
T6 Heat Treatment ◽  
Microstructure And Mechanical Properties ◽  
Different Temperatures

AbstractIn this study, the effect of solid solution temperature on microstructure and mechanical properties of the AA7075 alloy after T6 heat treatment was investigated. Following solid solution at five different temperatures for 2 hours, the AA7075 alloy was quenched and then artificially aged at 120∘C for 24 hours. Hardness measurements, microstructure examinations (SEM+EDS, XRD) and tensile tests were carried out for the alloys. The results showed that the increased solid solution temperature led to formation of precipitates in the microstructures and thus caused higher hardness and tensile strength.

Notched Tensile Fracture of Ti-6Al-6V-2Sn Welds at Elevated Temperature

2009 ◽  
Vol 79-82 ◽  
pp. 1137-1140 ◽  
Author(s):  
Lv Wen Tsay ◽  
C.L. Hsu
Keyword(s):  
Elevated Temperature ◽  
Grain Boundary ◽  
Tensile Tests ◽  
Tensile Fracture ◽  
Boundary Shear ◽  
Dimple Fracture ◽  
Laser Welds ◽  
Fracture Appearance ◽  
Notched Tensile Strength ◽  
Increasing Temperature

The notched tensile tests of Ti-6Al-6V-2Sn laser welds with distinct post-weld heat treatments (PWHTs) were carried out at 150, 300, and 450oC and the results were also compared with the mill-annealed base metal (BM). The BM specimen had the highest notched tensile strength (NTS) among the specimens being tested at room temperature but became the lowest at 450oC. At/above 150oC, all welds showed a decrease in NTS with increasing temperature. The cracks tended to grow along the α / β interface in the BM specimen. The formation of premature fine pores at the grain boundary in the weld with PWHT at 704oC accounted for the intergranular dimple fracture of the specimen. The fracture appearance of the as-welded (AW) and the 482oC-aged (W-482) welds comprised of mainly transgranular dimple and increased the extent of grain boundary shear at elevated temperature.

Mechanical Properties and Fracture Study of Alumina Dispersion Hardened Copper-Based Nano-Composite at Elevated Temperatures

2013 ◽  
Vol 829 ◽  
pp. 583-588 ◽  
Author(s):  
Ali Dalirbod ◽  
Yahya A. Sorkhe ◽  
Hossein Aghajani
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Fracture Surface ◽  
Yield Strength ◽  
Elevated Temperatures ◽  
Tensile Tests ◽  
Testing Temperature ◽  
Optical Microscope ◽  
Tensile Fracture ◽  
Different Temperatures

Alumina dispersion hardened copper-base composite was fabricated by internal oxidation method. The high temperature tensile fracture of Cu-Al2O3 composite was studied and tensile strengths were determined at different temperatures of 600, 680 and 780 °C. Microstructure was investigated by means of optical microscope and field emission scanning electron microscope (FESEM) with energy dispersive spectroscopy (EDS). Results show that, ultimate tensile strength and yield strength of copper alumina nanocomposite decrease slowly with increasing temperature. The yield strength reaches 119 MPa and ultimate tensile strength reaches 132 MPa at 780 °C. Surface fractography shows a dimple-type fracture on the fracture surface of the tensile tests where dimple size increases with increasing testing temperature and in some regions brittle fracture characteristics could be observed in the fracture surface.

Reheat Cracking Sensitivity of CGHAZ in Vanadium-Modified 2.25Cr1Mo Welds

2014 ◽  
Author(s):  
Yichun Han ◽  
Xuedong Chen ◽  
Zhichao Fan ◽  
Huaquan Bu ◽  
Yu Zhou
Keyword(s):  
Tensile Strength ◽  
Strain Rate ◽  
High Hardness ◽  
Hardness Test ◽  
Tensile Tests ◽  
Tensile Specimen ◽  
Coarse Grained ◽  
Reheat Cracking ◽  
Intermediate Temperature Range ◽  
Cracking Sensitivity

Over the past few years, some reheat cracks have been detected in the welding coarse grained heat affected zones (CGHAZ) of Vanadium-modified (V-mod) 2.25Cr1Mo reactor. Focusing on this problem, a series of Gleeble high temperature tensile tests were carried out on the simulation CGHAZ specimens of V-mod 2.25Cr1Mo at different temperature and strain rate, the reheat cracking sensitivity of CGHAZ has been assessed according to the reduction of area (RoA) of the specimens. Microstructural observation, hardness test and fractographic analysis also have been employed to ascertain possible causes for the effects of temperature and strain rate on the reheat cracking sensitivity. The results of tests show that the reheat cracking sensitivity of CGHAZ increases with a decreasing strain rate, it first increases and then decreases with a rising test temperature. The RoA presents a minimum value around 675°C, corresponding to the most sensitive temperature to reheat cracking. The comprehensive analysis reveals that the ductility of the simulated CGHAZ at elevated temperature is closely related to the tensile strength and the hardness of fractured tensile specimen. In the intermediate temperature range or at a slower strain rate, a relatively high hardness and relatively low tensile strength together results in a low RoA of the specimen and high reheat cracking sensitivity of CGHAZ metal.

scholarly journals Numerical predictions of crack growth direction in a railhead under contact, bending and thermal loads

2022 ◽  
pp. 108218
Author(s):  
Mohammad Salahi Nezhad ◽  
Dimosthenis Floros ◽  
Fredrik Larsson ◽  
Elena Kabo ◽  
Anders Ekberg
Keyword(s):  
Crack Growth ◽  
Growth Direction ◽  
Thermal Loads ◽  
Numerical Predictions ◽  
Crack Growth Direction
Sign in / Sign up

Export Citation Format

Share Document