Abstract:The boron carbide enforced aluminum matrix composite was fabricated by hot isostatic pressing. The size of Al-31%B4C composite is 3 mm×200 mm×5000 mm. The density, tensile strength and microstructure of the composite were characterized. Measure the 10B areal density of Al-31%B4C by neutron transmittance measurements, calculate the 10B areal density of the Al-31%B4C flat which thickness is 3.05 mm, the result is 0.035 2-0.038 9 g ? cm-2. The data analysis of results show that the areal density of 10B is uniform throughout the Al-31% B4C flat, and the results meet the requirements of the neutron absorption engineering flats.