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Recently, CaO added Mg-Al alloy sheets exhibited improved strength and elongation due to the effects of dispersion hardening and grain-refining by intermetallic compounds such as Al2Ca and (Mg,Al)2Ca and improved melt cleanliness. However, there is little study on these effects in Mg-Zn alloy system. In this study, as-cast ingots were prepared by melting Mg, Zn, Mg-25Y master alloy and Mg-3CaO master alloy in an electric resistance furnace under SF6+CO2 atmosphere. Sheet specimens were prepared by hot rolling process after indirect extrusion. The mechanical properties of CaO added Mg-6Zn-1.2Y specimens varied significantly with annealing process while the variation of mechanical properties of Mg-6Zn-1.2Y specimen was small. In addition, the texture of specimens with CaO (Ca in ICP analysis) was different from that of specimen without CaO. Therefore, we discussed the effect of microstructure and texture on mechanical properties and deformation behavior of CaO added Mg-6Zn-1.2Y sheet.

Mg2Si formed by the addition of Si in Mg-Al alloys is the very useful intermetallic compound. However, Mg2Si phases in the Mg-Al-Si alloys are prone to forming undesirable, coarse Chinese script shape, which will deteriorate the mechanical properties of Mg alloys. Therefore, in order to modify the Chinese script shaped Mg2Si phases in the Mg-Al-Si alloys, many methods have been studied such as alloying addition of Ca or P. This study was aimed at improving the mechanical properties of CaO added Mg-Al-Si alloys by the addition of alloying elements and varying cooling rate to change of morphology of Mg2Si and CaMgSi phases. The micro structure s of specimens were observed by OM and SEM, and the phase analysis was performed by XRD, TEM and EDS. To evaluate the mechanical properties of tested alloys, tensile tests were carried out at room and high temperatures.

This paper presents an analysis of inverse kinematics solutions for YH050 which is an industrial robot manipulator developed by Hyundai Heavy Industries Co. We propose three methods: numerical approach, geometrical approach and combined approach. These approaches are addressed through theoretical explanation and experimental verification.