Xia Tiandong

Microstructures Comparison of Stellite 6 Alloy by Self-Propagating High-Temperature Synthesis and Cast HS111 Alloy

Abstract The microstructures of as-SHSed Stellite 6 and as-cast HS111 were investigated by SEM, XRD and EPMA. It was shown that there is significant similarity in the microstructures of as-SHSed Stellite 6 and as-cast HS111. But carbides of continuous cast HS111 alloy can form single and uniform carbides phase.

Bulk MgB2 superconductor with high critical current density synthesized by self-propagating high-temperature synthesis method

Pure MgB2 bulk samples are successfully synthesized by self-propagating high-temperature synthesis (SHS) method. The experiments show that the best preheating temperature is 250°C, the highest Jc values of the prepared MgB2 reach 1.5×106A/cm2 (10K, 0.5T) and 1.7×106A/cm2 (20K, 0T) and the MgB2 particle sizes range from 2 to 5μm. The advantages of this method are that it is simple, economical and suitable for the manufacture of bulk MgB2 materials on industrial scale.

Study on Fretting Friction Coefficient between NiTi Shape Memory Alloy and Human Bone in Hank's Solution

Abstract The fretting friction coefficient between nickel titanium shape memory alloy (NiTi SMA) and hum Hanks solution by SRV multi-functional test system. The results show that the friction coefficient between pairs decrease with the lubrication effect coefficient in the acidic and alkaline media is greater than that in the normal situation. The friction coefficient between the bone and NiTi SMA tends to be stable with the increase of the amplitude in the four media. Because Hanks solution restrains the forming of worn scrap and its further development, the maximum wear depth and width of worn scrap and the volume of worn spot decrease to some extent compared to that in normal situations.

Synthesis and Electrode Characteristics of Mg(2-x)AlxNi Alloys by Combustion Synthesis

Abstract The Mg-based hydrogen storage alloy Mg 2- x Al x Ni( x =0.1-0.5) was synthesized by combustion synthesis. XRD indicates that a new phase with the cubic Ti 2 Ni structure appears in the product, and SEM shows that there are a large number of defects on the alloy surface. The effect of partial substitution of Al for Mg on the electrochemical performances of Mg 2 Ni was investigated. The results show that Al addition affects its electrode characteristics strongly. The electrochemical capacity and cycle lives of Al-containing alloys increase strongly compared to the Al-free alloy. This is attributed to the structure of a new phase (Mg 3 AlNi 2 ), and the formation of the protect layer of Al 2 O 3 . In addition, the results reveal that mechanical grinding is beneficial to improve activation behavior and the maximum electrode capacity, but can not improve the cyclic stability due to breaking of Al 2 O 3 protect layer.