In this study, the effect of the friction stir welding (FSW) was compared with that of the gas tungsten arc welding (GTAW) on the microstructure and microhardness of Cu-Ni alloy weldment. The weldment of 10 mm thickness was fabricated by FSW and GTAW, respectively. Both weldments were compared with each other by optical microstructure, microhardness test and grain size measurement. Results of this study suggest that the microhardness decreased from the base metal (BM) to the heat affected zone (HAZ) and increased at fusion zone (FZ) of GTAW and stir zone (SZ) of FSW. the minimum Hv value of both weldment was obtained at HAZ, respectively, which represents the softening zone, whereas Hv value of FSW weldment was little higher than that of GTAW weldment. These phenomena can be explained by the grain size difference between HAZs of each weldment. Grain size was increased at the HAZ during FSW and GTAW. Because FSW is a solid-state joining process obtaining the lower heat-input generated by rotating shoulder than heat generated in the arc of GTAW.

Titanium alloys are extensively used in high-temperature applications due to their excellent high strength and corrosion resistance properties. However, titanium alloys are problematic because they tend to be extremely difficult-tocut material. In this paper, the powder synthesis, spark plasma sintering (SPS), bulk material characteristics and machinability test of hybrid Ti₂AlC ceramic bulk materials were systematically examined. The bulk samples mainly consisted of Ti₂AlC materials with density close to theoretical value were synthesized by a SPS method. Random orientation and good crystallization of the Ti₂AlC was observed at 1100°C for 10 min under SPS sintering conditions. Scanning electron microscopy results indicated a homogeneous distribution and nano-laminated structure of Ti₂AlC MAX phase. The hardness and electrical conductivity of Ti₂AlC were higher than that of Ti 6242 alloy at sintering temperature of 1000°C~1100°C. Consequently, the machinability of the hybrid Ti₂AlC bulk materials is better than that of the Ti 6242 alloy for micro-EDM process of micro-hole shape workpiece.

Citations

Citations to this article as recorded by  

• Evaluation of Material Characteristics with Sintering Temperature in Ti2AlC MAX Phase Material using Spark Plasma Sintering Method
  Chang-Hun Lee, Gyung Rae Baek, Hee Sang Jung, Young-Keun Jeong, Myung Chang Kang
  Journal of Korean Powder Metallurgy Institute.2015; 22(3): 175.     CrossRef