Effects Of Ti, Zr Elements On The Microstrure And Properties Of Molybdenum Alloys

Molybdenum is a kind of commonly used high temperature metal, in order tofurther improve its high temperature performance, people usually add some alloyelements to reinforce its strengthen. There are not enough in-depth study for the alloyelement strengthening rule and its strengthening mechanism, resulted in the fallingbehind of the molybdenum alloy development. Aiming at this problem, this paperstudied the laws of effects of the Ti, Zr elements on the microstructure and propertiesof molybdenum alloys. Mo-Ti, Mo-Zr alloy were prepared by powder metallurgyprocess, and are been rolled and heat treated as well. And also, the influence rules ofhow molybdenum alloy properties are affected by alloy element Ti, Zr adding form(adding single metal, adding hydride) and adding amount were studied. Thestrengthening mechanism of alloy element Ti, Zr to Mo alloys were also investigated.Through the above research, the main conclusions drawn are as follow:By the adding of Ti, Zr elements, the room temperature tensile strength of matrixcan be effectively increased.After Ti, Zr elements are added to the molybdenum matrix, second phase oxideare able to form, in the deformation process of oxide, the movement of dislocationscan be effectively hindered, and the strength of the alloy can be increased. Zr candissolve into the matrix and generate solution reinforcement, meanwhile therefinement effect to the matrix grain were found. The oxide formed by Ti, Zr elementduring high temperature heat treatment will inhibit the restoration and growth of thegrain, delay the recrystallization process, enhance the high temperature stability ofmolybdenum alloy.Adding Ti element in a hydride form can get a higher room temperature tensilestrength than adding in the elemental form,25.1%of improve compared to puremolybdenum. But, to Zr element, adding it in a elemental form can get a higher room temperature tensile strength than adding in the hydride form,10.28%of improvecompared to pure molybdenum.With the increase of TiH2addition, the second phase increased, the strength of thealloy increases while the plasticity decreases. With the increase of ZrH2addition, thesecond phase increased, the strength of the alloy increased, plastic increased firstly andthen decreased on the addition dosage of0.12%, maximal plasticity show.After annealing, the strength of the alloy decreased, plasticity increased; Thestrength, plasticity of molybdenum alloy with same composition decreases with theincrease of annealing temperature; With the increase of the adding amount, thestrength of the alloy increase, its plasticity decrease.The addition of Ti element can greatly increase the strength of the alloy than Zrelement, and the addition of Zr element can refine the crystalline grain, increase theplasticity of the alloy.