Preparation of metal-fiber-reinforced Al-Si-Cu matrix composites in a vacuum-suction-casting process

Abstract

Lightweight alloys with high performance have become increasing popular in the world of materials engineering and science. In order to obtain high strength for an aluminum matrix alloy, the metal fiber in this work was embedded into the Al-Si-Cu matrix through a vacuum suction casting (VSC) process. Two different metal wires, i.e., copper-coated/copper-uncoated 304 stainless steel, separately, were used to prepare the Al-Si-Cu matrix composite. A microstructure investigation was conducted to study the interface reaction between the metal fiber and the matrix. The results show that the copper-coated wire was conducive to a tight connection for the metal fiber and the matrix, and it can greatly improve the comprehensive properties of the composite. The copper-coated, metal-fiber-reinforced Al-Si-Cu matrix (CC-Mf/Al) composite was further prepared with a different fiber diameter. In order to investigate the effect of the fiber diameter on the microstructure and properties, a microstructure observation of the CC-Mf/Al composite was conducted using scanning electron microscopy (SEM). Properties testing was carried out using a P300 electronic universal testing machine, a MHVD-1000IS microhardness tester and a FT300 resistivity tester. The experimental data indicate that the mechanical properties of the composite increase first and then decrease as the diameter of the fiber increases. When the diameter of the copper-coated fiber is 0.1 mm, i.e., a volume fraction of 0.17 %, the tensile strength of the CC-Mf/Al composites reaches a maximum of 341.04 MPa, which is 49.33 % higher than that of the original aluminum alloy. The elongation and microhardness are 54.24 mm and 129.1 HV, respectively. The resistivity of the CC-Mf/Al composites is lower than that of the copper-uncoated metal fiber-reinforced Al-Si-Cu aluminum matrix (CU-Mf/Al) composite. Keywords: vacuum suction casting, CC-Mf/Al and CU-Mf/Al composite,microstructure, mechanical properties Visoko kvalitetne lahke Al zlitine postajajo vse bolj popularne na podro~ju in`eniringa in znanosti materialov. Avtorji so zato, da bi izdelali lahek kompozitni material z visoko trdnostjo, v matrico na osnovi Al-Si-Cu vgradili kovinska vlakna. Za to so uporabili postopek vakuumskega sesalnega litja (VSC). Za izdelavo kompozita z Al-Si-Cu matrico (CC-Mf/Al) so izbrali dve razli~ni vrsti kovinskih vlaken in sicer: z bakrom prevle~eno in neprevle~eno jekleno`ico iz nerjavnega jekla tipa 304. Izvedli so mikrostrukturne preiskave in {tudirali reakcije na meji med kovinskimi vlakni in matrico. Rezultati so pokazali, da je matrica, ki vsebuje z bakrom prevle~ena vlakna, v celoti prevodna, kar je mo~no izbolj{alo lastnosti kompozita. Nadalje so izdelovali {e CC-Mf/Al kompozite, oja~ane z jeklenimi vlakni razli~ne debeline. Vpliv debeline vlaken na mikrostrukturo in lastnosti CC-Mf/Al so analizirali z vrsti~nim elektronskim mikroskopom (SEM). Mehanske lastnosti kompozitov so dolo~ili s pomo~jo elektronskega univerzalnega trgalnega stroja P300. Trdoto kompozitov so dolo~ili na merilniku m...