Utjecaj otopine u čvrstom stanju i starenja na mikrostrukturu i mehanička svojstva kompozita čestica SiCp/Al-Si-Cu-Mg

The SiC particles (SiCp, mass fraction 30 %) reinforced with the Al-Si-Cu-Mg matrix composite have been prepared using one-way press method, sintering, and hot extrusion. The composite was subjected to solid solution treatment at temperatures of 470 °C, 485 °C, 500 °C, 515 °C, and 530 °C for 4 h. The sample was then subjected to ageing treatment at temperatures of 160 °C and 180 °C during different times after solid solution treatment at 515 °C for 4 h. The microstructure and mechanical properties of the SiCp/Al-Si-Cu-Mg matrix composite under the different ageing and solid solution treatments were tested using SEM and TEM microhardness analysis. The results show that the white granulated metallic compounds of the SiCp/Al-Si-Cu-Mg composite materials, which are formed in the sintering process of composite materials, dissolve back after the solid solution treatment at different temperatures. The higher the solid solution temperature, the more metallic compounds dissolve back. The microhardness of the composites reached maximum after solution treatment at 515 °C for 4 h. Following the ageing treatment and with the prolongation of ageing time, the hardness of the composite material reached “double peak” phenomenon. With the increase in ageing temperature, the hardening speed of the composite material also increased, but at the same time, the hardening ability had reduced. After the ageing treatment, the second phases of the composite are discoid Al5Cu6Mg2. This work is licensed under a Creative Commons Attribution 4.0 International License.Pripravljen je kompozit čestica SiC (SiCp) u masenom udjelom 30 % u matrici Al-Si-Cu-Mg prešanjem, sinteriranjem i ekstrudiranjem. Kompozit je 4 sata bio izložen otapanju u čvrstom stanju pri 470 °C, 485 °C, 500 °C, 515 °C i 530 °C. Nakon toga na uzorak je 4 sata pri 515 °C djelovalo otapanje u čvrstom stanju, a zatim su uzorci starili različito vrijeme pri temperaturama 160 i 180 °C. Mikrostruktura i mehanička svojstva kompozita proučena su tehnikama pretražnom i transmisijskom mikroskopijom te analizom mikrotvrdoće. Pri sinteriranju kompozita SiCp/Al-Si-Cu-Mg nastaje bijeli zrnasti metalni spoj koji se otapa u čvrstu otopinu pri različitim temperaturama. Što je viša temperatura čvrste otopine, više se otopi metalnog spoja. Mikrotvrdoća doseže maksimum pri izlaganju reakcijama u čvrstom stanju pri 515 °C kroz četiri sata. Nakon starenja i s produljenjem starenja tvrdoća materijala pokazuje dvostruki vrh. S povišenjem temperature povećava se brzina očvršćivanja, no istodobno se smanjuje mogućnost očvršćenja. Druga faza kompozita nakon starenja je diskoidni Al5Cu6Mg2. Ovo djelo je dano na korištenje pod licencom Creative Commons Imenovanje 4.0 međunarodna