Authors: Xiao Ping Luo, Lan Ting Xia, Ming Gang Zhang
Abstract: The effect of Cd and Sb addition on the microstructural and mechanical properties of as-cast AZ31 alloys was investigated and compared. The results indicate that the difference of Sb and Cd in the microstructure and mechanical properties of as-cast AZ31 magnesium alloy is significant. Addition of 0.15%Sb (mass fraction) to AZ31 alloy can refine the matrix and β-Mg17Al12 phase but not form a new phase Mg3Sb2. Oppositely, by addition of 0.3-0.7% Cd to AZ31 alloy, Cd was dissolved into the AZ31 alloy, the phase composition did not change but was refined also. Accordingly, the Cd-refined AZ31 alloy exhibits higher tensile and impact toughness and Brinell hardness properties than the Sb- refined one. The difference of Sb and Cd in the mechanical properties is possibly related to the solid solution of Cd into the matrix and formation of Mg3Sb2 which has the same close-packed hexagonal structure as α-Mg.
197
Authors: Zheng Tian, Zhan Yi Cao, Jian Meng
Abstract: The effect of yttrium addition and heat treatment on the mechanical properties and microstructure of AM60 magnesium alloy have been investigated using X-ray phase analysis, microstructure investigation, tensile test, hardness measurement and fracture surfaces analysis. The results showed that the mechanical properties of the alloys were obviously improved with the addition of yttrium no more than 1.0%. The reinforcement of the alloys resulted from the appearance of Al2Y phase. After solid-solution treatment (T4), the Mg17Al12 phase almost dissolved in Mg matrix, but the rare earth compounds Al2Y phase was rather stable. The ultimate tensile strength σb was improved, but the yield strength σ0.2 and elongation δ were only slightly changed. After solid-solution + aging treatment (T6), the Mg17Al12 phase precipitated again and their morphology was changed. The yield strength σ0.2 was improved.
1319
Authors: Yong Hua Li, Xin Jun Liang, Tao Fan
Abstract: Biomedical titanium alloys can be used for replacement and repair surgeries of human hard tissues. In recent years, the new b type titanium alloys with low elastic moduli and excellent biocompatibility have been developed by choosing low cytotoxic elements. Furthermore, new type of porous titanium alloys can lower elastic modulus effectively and contribute to the ingrowth of tissues. The present research status of new b type titanium alloys and porous titanium alloys have been introduced in this literature, the future research trend has also been discussed.
2009
Authors: S.G. Shabestari, R. Gholizadeh
Abstract: Dense precipitation of various intermetallic compounds is a common feature in the microstructure of Al-Si piston alloys. In this investigation, microstructure of LM13 alloy and three high Cu-containing Al-Si piston alloys with different amounts of Ni, Fe, and Mn were studied by means of optical microscopy (OM) and scanning electron microscopy (SEM). Chemical composition of the phases was determined by using energy dispersive X-ray analysis (EDX). The precipitation of the phases was studied through thermal analysis of the solidifying samples. Also, tensile properties and hardness of the samples were measured. The results showed that the various intermetallics such as Al12(FeMn)3Si2, Al3Ni, Al9FeNi, and Al3CuNi precipitated during the solidification. The high Cu-containing alloy with optimum levels of Ni (1.8 wt.%), Fe (0.75 wt.%), and Mn (0.3 wt.%) has the highest tensile strength (250 MPa) and hardness (110 BHN) among the other alloys.
289
Authors: Dai Dong Zhang, Xiao Ru Zhang, Xiu Qin Ge, Da Qing Fang, Xue Hua Yu
Abstract: The effect of low content of Ca (0.9 or less)on the microstructure and mechanical properties of AZ63 alloys were studied in this paper. The results show that, adding a small amount of Ca , the alloy does not generate Al2Ca phase. The calcium dissolved into the matrix or compound phase and have an uneven distribution, but it can improve the distribution of β-Mg17Al12 phase ,refine the grain and improve the mechanical properties. Adding 0.3%Ca to AZ63 (WT%), the microstructure and mechanical properties of alloy are more ideal.
579