The Preparation And Properties Of Fe-Ni Metal-based Magnetostrictive Alloys

Fe-Ni metal-based magnetostrictive materials are widely used in oil,chemical raw material storage,industrial process,biochemistry,medicine,food and beverage,tank farm management,gas station underground inventory,various liquid storage tanks of industrial level measurement,precise flow control,deep-sea submarine valves and watertight door sealing safety control etc..At present,the alloys prepared by Chinese have some shotcomings,like poor plastic toughness low magnetostriction property and poor stability of signal.To solve this problem,Fe-Ni metal matrix magnetostrictive alloys were prepared by adding different alloy elements,and different processing technology.Using SEM,EDS,XRD,VSM and tensile test means to systematically study the effects of suction casting,forging and heat treatment on microstructure,phase,mechanical properties,physical properties and magnetostrictive properties.In this paper,the purity of 99% of Fe,Ni,Cr,Co,Ti,Si,Al powder was chosen as the raw material.The powder was mixed in different ingredients,then melted and suctioned into alloy cast rods whose diameter is 3 mm in a vacuum of 2.5×10-3 Pa under argon.The composition had no effect on Fe-Ni alloy's phase,four kinds of alloys had the same phase structure,which was face-centered cubic structure Fe0.64Ni0.34 solid solution phase.And the properties of Fe46Ni43Cr6Ti3 SiAl obtained by casting is best(HV=217 HV0.5/1,?b=477 MPa,?=9.7%,?=0.52 ??·m,Hc=1818 A/m,Bs=804 mT,?s=20.0 ppm).The alloy cast rods were repeatedly forging at the initial forging temperature of 1150 ?,the final forging temperature of 200 ?.Finally the alloy thin rods having a diameter of 1.2 mm can be obtained.The study found that forging didn't change alloys' phase,and improved performance of alloys.The properties of Fe46Ni43Cr6Ti3 SiAl is best in forging alloys(HV=278HV0.5/10,?b=821 MPa,?=2.10%,?=0.69 ??·m,?s=26.1 ppm).The alloys after forging were vacuum heat treatmented at 550 ?,incubated for 2 h.Study found that the heat treatment also did not change the phase structure of the alloys,butthe internal stress was eliminated,the grain size was refined,and the properties of the alloys were further improved.The properties of Fe46Ni43Cr6Ti3 SiAl alloy were best in alloys obtained after heat treatment.Its properties were as followed(HV=356 HV0.5/10,?b=871 MPa,?=8.84%,?=0.59 ??·m,?s=30.8 ppm).Fe-Ni magnetostrictive alloy(Fe46Ni43Cr6Ti3SiAl)which was prepared in this paper and had face-centered cubic structure Fe0.64Ni0.34 solid solution phase had a high saturation magnetostriction coefficient(30.8 ppm),the coercive force(1940 A/m)was a little high,the mechanical properties of Fe46Ni43Cr6Ti3 SiAl alloy(?b=871 MPa)is a little lower than imported Fe-Ni alloy's(?b>930 MPa).And Fe46Ni43Cr6Ti3 SiAl alloy alloy's conductivity is good.It is very important to deeply study the influence of adding alloying elements and preparation on magnetic and mechanical properties of Fe-Ni alloy by changing the alloy composition or improved preparation process.So that Fe-Ni magnetostrictive alloy with excellent comprehensive properties can be prepared.