In situ synthesis of ZrB2 in Al matrix by reactive spark plasma sintering of mechanically alloyed powder

Spark plasma sintering was utilized to synthesize in situ Al-ZrB2 nanocomposite from reactive powders.Reactive powder mixtures of Al-ZrO2-B2O3-B were prepared by mechanical alloying (MA) in a high energy planetary ball mill. Initial powder mixtures were milled for 30 h at 450 rpm and 20 h at 600 rpm milling speeds to prevent SHS reaction and formation of ZrB2 during mechanical alloying. Reactive powders were sintered successfully by spark plasma sintering at 550 oC for a sintering time of 10 min. X-ray diffractometery (XRD) was used to study the structuralevolution during milling and after sintering. Powder particles and sintered samples were examined by scanning electron microscopy (SEM) for microstructural investigations. Hardness measurements were conducted on the cross section of sintered samples. Sintering of reactive powders led to in situ formation of ZrB2 nano particles within the Al matrix. The hardness of SPSed nanocomposites obtained from reactive MAed powders was measured to be 240 HV with a reasonable density

کلیدواژه ها:

In situ composite ، Spark plasma sintering ، Al-ZrB2