The Effect Of Varying Phosphorus-Content On The Impact Strength Of 93W-4,9Ni-2,1Fe Heavy Alloy

Abstract

When P is added up to 300 ppm to a sintered 93W-4,9Ni-2, 1Fe (mass-%) alloy, the impact energy decreases significantly with the P concentration even after heat treatment at 1150-degrees-C in N2 atmosphere and water-quenching. The result shows definitely that the presence of P at the levels normally found in the raw material powders produces an embrittlement of this alloy. The structure and the composition of the fracture surface are consistent with the previous suggestion that the embrittlement arises from P segregation at the grain-matrix interface. The impact energy decreases with decreasing heat treatment temperature and cooling rate in agreement with the general segregation behaviour of impurities at interfaces.