Study Of Low Activation Vanadium Alloys Prepared By Mechanical Alloying

Vanadium-base alloys nominally containing4-5wt%chromium and4-5wt%titaniumhave been identified as the most viable materials for fusion reactor applications becausethey have lower long-term activation,lower irradiation afterheat,lower biological hazardpotential and thermal stress factor,better creep resistance,compatibility with coolants suchas liquid alkali metals,and better mechanical formability.The process o f lo w-act ivat ion V-4Cr-4Ti allo y prepared by mec han icalallo ying was explored. XRD linear analysis（double-Voigt function） method was usedto analyze and characterize the crystallite size and lattice distortion of V-4Cr-4Ti-1.8YH₂and V-10Cr-10Ta-1.8YH₂alloy powder after milling.Then the crushing mechanism ofvanadium alloy powder was discussed.The crystallite size and lattice distortion of thepowder prepared by the milling process were analyzed and characterized to explore thevanadium the crushing mechanism.XRD linear analysis and SEM test results show that,when choose the appropriate ball to powder ratio（7:1）,milling speed（200rpm）,millingatmosphere（99.999%argon）,milling time（60hr）,with the exception of some residual Cr,thepowder has been alloying.There is no pollution caused by grinding balls and the ballmilling tank in the vanadium alloy.After milling60hr,the crystallite size and the latticedistortion of the powder are12.5±0.6nm and0.533×10^-2±0.269×10^-3,respectively;whenthe ball to powder ratio is20:1,and the other conditions are all the same,there is obviousZrO2grain caused by grinding balls and the ball milling tank in the vanadium alloy.Aftermilling60hr,the crystallite size and the lattice distortion of the powder are15.8±2.4nmand0.497×10^-2±0.477×10^-3,respectively.Vanadium alloys were fabricated by the process of mechanical alloying （MA）-sparkplasma sintering（SPS）-hot isostatic pressing（HIP）-annealing treatment.The mechanicalproperties of alloys were tested by the micro-hardness tester and the tensile testingmachine.It showed that the micro-hardness of different components of the vanadium alloyingot are very different,such as the hardness of the vanadium alloy ingots is significantlyhigher which W,Ta,TaC power was added to vanadium alloy.With the increase of theamount of the added power,the micro-hardness of the alloy increases,and the brittleness is also relatively large.YH₂added to the V-4Cr-4Ti can significantly improve the strength and ductility of the alloy.V-4Cr-4Ti-1.8YH₂alloy,with the suitable heat treatment,it can increase the alloy yield strength,tensile strength and elongation significantly.The alloy V-4Cr-4Ti-1.8YH₂which annealled at1100℃has the best comprehensive mechanical properties:yield strengthof665MPa,the tensile strength of909MPa,elongation of16.7%.