تأثير اضافة الكروم على الصفات الميكانيكية للمادة المركبة ذات الاساس شبه المعدني (NiAl-Al2O3)

Abstract

In this investigation NiAl-based composites containing a dispersion of Al2O3 particles are prepared by sintering technique at 1350°C for 90 min. in an argon atmosphere. Intermetallic compound NiAl was prepared from a mixture of nickel and aluminum powders by using reactive sintering technique at 600°C for 12 Hrs. in an argon atmosphere. To improve the ductility of NiAl three weight percents of Cr (3.5, 4, 4.5 wt %) were added to the composite (NiAl-Al2O3). Series of experiments showed that: -adding of (Al2O3) to (NiAl) leads to increase its compressive strength and its hardness but with a decrease in its ductility;-adding Cr to the intrmetallic composite (NiAl-Al2O3) leads to increase its compressive strength and its hardness with an ability to improve its ductility. An addition of (4.5 wt% Cr) to the composite containing (10wt%Al2O3) led to improve the compressive strength by (25%), hardness by (9%) and ductility by (94%) in comparison with that containing no Cr.