Microstructure and homogeneity of semi-solid 7075 aluminum tubes processed by parallel tubular channel angular pressing

Autor: Vahid Pouyafar, Akbar Javdani, Ali Fata, Ghader Faraji, Ramin Meshkabadi
Rok vydání: 2017
Předmět:
Zdroj: Metals and Materials International. 23:1019-1028
ISSN: 2005-4149
1598-9623
DOI: 10.1007/s12540-017-6760-3
Popis: Semi-solid processing is a new developing technology for the fabrication of intricate parts at low temperatures in comparison with conventional casting routes. In this research, a parallel tubular channel angular pressing (PTCAP) was used as a pre strain-inducing process, and the influence of the number of PTCAP passes and semi-solid heating parameters on the microstructural characteristics of Al7075 tubes was investigated. The results demonstrated that PTCAP process could successfully be used as a best pre-straining method for tubular samples showing semi-solid microstructures. As the temperature is increased, the solid particle size first decreased, then increased, and gradually became more spherical. The appropriate condition for the subsequent semi-solid forming process was gained at reheating temperature of 620 oC. The suitability of this temperature was confirmed by the uniform distribution of grains. The grain size and shape factor both increased along with increasing the holding time. The distribution of the solid particles was strongly dependent upon the holding time and became uniform as the holding time increased. Comparison of the grain size and shape factor between ECAPed and PTCAPed samples revealed a high capacity of the PTCAP process as a strain-inducing stage. Also the two-pass PTCAP samples exhibited higher hardness than one-pass treated samples in the semi-solid state.
Databáze: OpenAIRE
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