Average Tensile Strength Of Joint Research Articles

Study on microstructure and mechanical properties of single crystal/powder superalloy pulsed current diffusion bonded joints

To optimize the overall structure design of the aero-engine turbine disks, the study of pulsed current diffusion bonding on the second generation nickel-based single-crystal superalloy DD5 and the third generation powder superalloy FGH98 was performed, and high-quality joints were obtained after post-welding heat treatment(PWHT). The microstructure and element diffusion were analyzed by using SEM and EDS, and the microhardness and room / high temperature tensile strength were analyzed. It can be seen from the results that with the pulse current, the diffusion bonding produced a high-temperature gradient from the interface to the base metal, which protected the base metal. The precipitation phase of γ′ phase within the connection interface near the FGH98 side within 200 µm exhibits very small granular-large-size unstable petals-larger granular similar to the base metal. The γ′ phase in DD5 grows abnormally at the interface. Large granular γ′ enhancement phases occurred on the FGH98 side after heat treatment with no significant changes on the DD5 side. The microhardness of the joints is not less than 400HV; and from DD5 side to FGH98 side, the hardness decreases first and then increases. The average tensile strength of the joints at room temperature is 1078 MPa, which is 99% of the tensile strength of the base metal with low performance. The average tensile strength of joints at high temperature (650 °C) is 1089 MPa, which is equivalent to the strength of the base metal.

Impact of Nb on microstructure and properties of oscillating laser-CMT hybrid welding joints of A7204P-T4 aluminium alloy sheets

In this paper, fibre laser-cold metal transfer arc (CMT) and oscillating fibre laser-CMT hybrid welding processes were adopted for A7204P-T4 aluminium alloy sheets with thickness of 6 mm. Furthermore, the effect of Nb content on microstructure and mechanical properties, the metallurgical behaviour, and influence mechanism were investigated. Oscillating laser effectively reduced the weld porosity and increased the joint’s elongation after fracture by 81%. With the addition of Nb, the heterogeneous nucleation significantly refined weld grains and removed columnar and dendritic structures which attributed to the solute segregation of Nb and primary phase NbAl3. The average tensile strength of joints with 0.43%, 0.74%, and 0.83% Nb mass fractions to 336, 334.5, and 341 MPa, respectively.

Performance of Embeded of Precast Beam Type Wet and Dry Joint at Maximum Moment

Research of perform of embedded precast beam was result many data (a) average tensile strength of joint between plate embedeed with plate joint was 628,55 Mpa (b)average tensile strength of joint between plate with reinforce bar D12,59 was 597,16 Mpa for tensile strength of plate with failure at reinforce bar (c) average tensile strength of reinforce bar D12,59 was 605,23 Mpa and yield strength was 425,87 Mpa (d)average tensile strength of plate 4,58 mm thick was 456,86 Mpa and yield strength was 335,02 Mpa. For welded joint need several control quality so that no hole in that perform of welded couse can decrease tensile strength of joint. Conclusion of this research is embedded for precast concrete type wet and dry can be used for construction of joints of beam.

Comparative study on laser welding characteristics of aluminium alloy under atmospheric and subatmospheric pressures

Laser bead on plate welding of 10 mm thick aluminium alloy under atmospheric and subatmospheric pressures were comparatively investigated. With the decrease of ambient pressure, the penetration depth increased sharply at first and then gradually levelled off. The largest penetration depth could reach 8·7 mm when welded under the pressures of 101 Pa, while only 4·9 mm under atmospheric pressure. Weld bead without any porosity was produced under ambient pressures of 10−1 Pa. The average tensile strength of joints welded under the pressure of 101 Pa was 300·2 MPa. The tensile strength remained constant as the ambient pressure decreased further. The shielding effect of plasma plume on laser beam was suppressed as the ambient pressure decreased. Therefore, the laser power deposition inside the keyhole was enhanced effectively. Under subatmospheric pressure, the porosity defects were eliminated effectively due to the keyhole stability and the change of liquid flow, i.e. moving upward along the rear wall of keyhole.