Effect Of Microalloying And Magnetic Field Treatment On Solidification Structure And Mechanical Properties Of Al-10%Ni Alloy

Al-Ni alloy is an important light structure materials, which inherits much advantages of the cast aluminum alloys, for instance, good castability, high electrical, thermal conductivity, specific strength, good fluidity and high temperature oxidation resistance, etc. The two processes about alloying and magnetic treatment are always been researched popularly by scholars. The effect of alloying treatment is purify melt and metamorphic refinement, magnetic treatment has the advantage of no pollution, convenient and remarkable effect. In this article, the effect of trace element RE, Sr, Zr, steady magnetic field, pulse magnetic field, alternating magnetic field on the solidification structure and mechanical properties of Al-10%Ni alloy were investigated. Some conclusion can be drew:RE, Sr, Zr alloying treatment have significantly changed the solidification structure of Al-10%Ni alloy. With the increase of RE content, Al3 Ni phase after the first refining roughening. The microstructure was the most obvious when the content of RE was 0.4%. With the increase of Sr or Zr content, Al3 Ni phase was gradually refined. After adding RE, Sr or Zr, the alloy appears Al3 Ce, Al4 Ce,Al Sr,Al2 Zr,Al3Zr. With the increase of RE or Sr content, the hardness decreased. With the increase of Zr content, the hardness increased. After adding 0.4%RE or 0.6%Sr, the tensile strength and elongation decreased. After adding 0.6%Zr, the tensile strength increased 20%, and the elongation decreased 46%.The solidification structure of Al-10%Ni alloy was significantly improved by the steady magnetic field treatment. With the increase the degree of alignment in the range of 0-1.5T, Al3 Ni phase is distributed homogeneously and gradually aligned at parallel to the direction of the magnetic field. The degree of alignment increased and the spacing reduced. The growth of α-Al(311) crystal face was inhibited, and the preferential orientation is formed in(111) crystal face. The diffraction intensity of the crystal face(111) is enhanced, in other direction the intensity is weakened or even disappeared, the crystal of Al3 Ni phase is oriented with c-axes. After the steady magnetic field, the lattice constant of α-Al are generally lower and the hardness increase overall. When the magnetic intensity is 1.1T, the tensile strength increase 3.1% and the elongation decrease 41.6%.Under the effect of pulse magnetic field, the solidification structure of Al-10%Ni alloy can be remarkably refined by changing the process parameters, and the long-strip Al3 Ni phase is transformed form small granules. With the increase of pulse voltage in the range of 0-300 V, the Al3 Ni phase is to refine the roughening. When the pulse voltage is 250 V, the Al3 Ni phase is the smallest. With the increase of pulse frequency in the range of 0-10 Hz, Al3 Ni phase is refined gradually. Whether or not applying pulse magnetic field, Al3 Ni phase is refined gradually with the decrease of pouring temperature or casting temperature. The crystal orientation of α-Al in(200) crystal face was inhibited, and the new preferential orientation was formed in(111) and(311) crystal face. When the pulse voltage is 200 V, the tensile strength increase 40% and the elongation increase 20%.With the increase of alternating voltage in the range of 0-250 V, after Al3 Ni phase is to refine the roughening. When the alternating voltage is 150 V, the Al3 Ni chain organization is the smallest. When the alternating voltage is 250 V, despite the Al3 Ni phase become coarsening, but appear more serious broken crystal. With the increase of pouring temperature, the Al3 Ni phase become coarsening. With the increase of pouring temperature, the Al3 Ni phase is refined. After apply on alternating magnetic field, the α-Al in(111) surface formed a preferential orientation, and the(200) preferred orientation was inhibited. Al3 Ni phase in(112),(020),(131) crystal face had a new preferred orientation. The tensile strength and the hardness of the alloy are improved by the alternating magnetic field. When the alternating voltage is 200 V, the tensile strength increase by 5%, the hardness increase by 8.8%, while the elongation decrease by 11%.