Papers by Keyword: LY12

Abstract: Galvanic corrosion behavior of TC4 titanium alloy coupled LY12 aluminum alloy was investigated in 3.5% NaCl solution. Particular attention was given to the effect of three different oxidation films. Galvanic corrosion test was conducted on TC4 titanium alloy which coupled LY12-sulfuric acid anodic film (LY12/A(S)), LY12-chromic acid anodic film (LY12/A(Cr)), LY12-hard anodic film (LY12/A(S) hd) and bare LY12, respectively. Galvanic corrosion current (Ig) and average galvanic current density (Ig’) were monitored. Corrosion morphology was observed by camera and corrosion mechanism was discussed. The results show that the three anodic films improve the corrosion resistance of the anode in different magnitudes. LY12/A(S) hd is found to be least susceptible to galvanic corrosion when coupled TC4 titanium alloy. LY12/A(S) and LY12/A(Cr) are found to be moderately susceptible to galvanic corrosion. But the bare LY12 is highly susceptible to galvanic corrosion in corrosive environment.

Abstract: LY12/TC4 joints have wide applications in many industrial areas such as aerospace, nuclear and chemical industries. In the present study, TC4 alloy and LY12 alloy with and without aluminum thin film was produced under low temperature of 380 ^oC. The microstructure and mechanical properties of the joints were investigated. The addition of the Al thin interlayer had largely improved the interfacial microstructure and shear strength of the joints. The average shear strength of LY12/Al/TC4 joints was 64.3 MPa which was 2.5 times larger than the LY12/TC4 joints’ strength. The shear fracture mainly occurred on the interface of LY12 and TC4 from the XRD result of fracture surfaces.

Abstract: LY12 aluminum alloy was welded with vacuum electron beam welding, the effect of welding speed and electron beam current on the weld microstructure and mechanical properties of welding joints were studied, the results were shown that with the increasing of welding speed or decreasing of electron beam current, the grains in weld metal were refined, so the joint strength were increased. When the electron beam current was 18mA, the welding speed was 1000mm/min, the grains of weld metal were the finest, and the tensile strength was 373.2MPa. In addition, the micro-hardness of weld metal was much lower than base metal and heat affected zone, and the heat affected zone had certain softening phenomenon. With the increasing of welding speed or decreasing of electron beam current, the micro-hardness of weld metal was increased respectively.

Abstract: Galvanic corrosion behavior of Ti-1023 titanium alloy coupled to LY12 aluminum alloy was investigated in 3.5% NaCl solution. Particular attention was given to the effect of anodized coatings on corrosion behaviors of Ti-1023/LY12 galvanic couple. Galvanic test was conducted on the following couples: Ti-1023/LY12, Ti-1023/anodized LY12 and anodized Ti-1023/anodized LY12, respectively. Corrosion properties including open circuit potential (Eoc) of each material, galvanic corrosion potential (Eg) and galvanic corrosion current (Ig) of the couples were monitored. Corrosion morphology was observed by optical microscope (OM) and corrosion mechanisms were analyzed and discussed. It was showed that anodized coatings significantly decreased Eg and Īg of the couples and provide effective protection of the anode from suffering corrosion attack. Only slight localized corrosion was detected on anodized LY12 alloy in the two anodized couples and the LY12 in anodized Ti-1023/anodized LY12 couple was found to be least susceptible to galvanic corrosion. The LY12 alloy in the bare couple: Ti-1023/LY12, was found to be highly susceptible to galvanic corrosion and suffered severe uniform and localized corrosion attack

Abstract: In this paper, we introduce the squeeze casting process to produce flange. This article also introduces the optimized roughcast of flange, the cruces of the die design, the main structure parameters and the working traits of the die. The result shows that using squeeze casting method to produce flange not only can get the qualified part, which also greatly increase the material utilization together with enormously save processing time and processing costs at the same time.

Abstract: Galvanic properties were evaluated on bare and anodized Ti-1023 titanium alloy which coupled to Ni-electroplated, Zn-electroplated, Cd-electroplated 30CrMnSiA and anodized LY12, respectively. Corrosion properties including open circuit potential (Eoc) of each material, galvanic corrosion potential (Eg), and corrosion current (Ig) of the couples were monitored in conjunction with a Model 263A potentiostat system. Corrosion current density (Īg) and average value of corrosion potential (Ēg) were calculated from Ig-time and Eg-time curves, respectively. Corrosion morphology was observed on a optical microscope (OM) and corrosion mechanisms were analyzed and discussed. The corrosion resistance of Ti-1023/LY12 couple was significantly improved by Ti-1023 anodized coating. However, the coating accelerated the dissolve of the three electroplated coatings in the other galvanic couples, resulting in a heavy corrosion attack on 30CrMnSiA steel.

Abstract: By analyzing morphology, weight gain, pitting depth, potential and AC impendence in corrosion course, initial pitting behavior of LY12 aluminum alloy in simulated marine atmosphere was studied. Results indicated initial pitting of LY12 was affected much by Cl- sedimentation and atmosphere humidity, little by temperature below 35°C. Weight gain and pitting depth increased with rising of Clsedimentation quantity, humidity and temperature. Correlation of weight gain and time fitted Model Boltzman. In initial pitting course of LY12, open circuit potential changed little and Nyquist graph had the characteristic of adsorbent resist system.