The Study On The Glass Forming Ability,Thermal Stability And Mechanical Properties Of Cu-based Bulk Metallic Glasses

In this paper, the glass forming ability, thermal stability, mechanical properties under room temperature and microhardness of (Cu6oZr33Ti7)ioo-x-Alx(x=0,2,4,6,8,10) bulk amorphous alloys have been investigated. Kinetics on non-isothermal crystallization, effect of cooling rate on crystallization and magnetic properties by using differential scanning calorimetry (DSC) of (Cu60Zr33Ti7)100-xAlx(x=0,6) bulk metallic glasses have studied.Obtains the thermodynamical coordinate of the amorphous alloy through DSC, calculates the parameters of the glasses forming ability through these parameters such Trg, γ and β, through these parameters, discovered that the glasses forming ability of the Cu60Zr33Ti7metal is not so good, in order to enhance the glasses forming ability of the (Cu60Zr33Ti7)-100-xAlx alloy, we attempt to increas2%Al in Cu60Zr33Ti7alloy, through the above attribute parameter we discover that adding2%Al in Cu60Zr33Ti7alloy, it's glasses forming ability is improved. In order to the alloy proportion with the best glasses forming ability, we continued to add4%,6%,8%Al in Cu60Zr33Ti7, and through the suction copper casting, we obtain the4mm and6mm alloy stick, through the XRD diffraction result, we know that adding2%and6%Al in Cu60Zr33Ti7can obtain the diameter4mm amorphous alloy stick,(Cu60Zr33Ti7)94Al6can obtain the diameter6mm amorphous alloy stick. So we can draw the conclusion that adding6%Al in Cu60Zr33Ti7alloy have the highest glass forming ability.In research the cu-based amorphous alloy's crystallization dynamics, we discover that along with the promotion of the heating rate,(Cu60Zr33Ti7-)100-xAlx demonstrated the dynamic effects (along with the elevation of the heating rate, the characteristic temperature traverse to high temperature),(Cu60Zr33Ti7)100-xAlx presented three crystallization peaks under the lOk/min heating rate, but along with heating rate's enhancement, three crystallization peak merge to a crystallization peak, this is because of along with the heating rate enhancement, the preceding crystallization process has not carried on, the latter crystallization process already started. After the computation, by Kissinger equation,we obtained the three metal glass's crystallization activation energy Ec of (Cu6oZr33Ti7)ioo-xAlx(x=0,6) is115.84kJ/mol,105.72kJ/mol; By Ozawa equation obtained the three metal glass's crystallization activation energy Ec of (Cu6oZr33Ti7)100-xAlx(x=0,6)is122.51kJ/mol,113.02kJ/mol.But the crystallization activation energy calculated by the two methods existence certain error, but it is not big. Adding6%Al in Cu6oZr33Ti7, reduced the amorphous alloy's crystallization activation energy slightly.In the study of the mechanical properties affect of Al added to (Cu6oZr33Ti7)100-xAlx(x=0,2,4,6,8,10) bulk metallic glass,we find that, with the increase of the Al content, compressive strength and microhardness showed the same trend, firstly reduce then rise, with the content of Al at6%,the compressive strength and microhardness reached to the highest point (2010Mpa,767.6HV), then reduce.The relative compression rate with the change of the Al content decreased at first, then increased, and when the Al content is6%, it reach to the highest point (10.66%), and then reduced. Study on the fracture morphology was found, Al content is6%, context shaped stripes (dimple) becomes uniform and fine, density is very high, which explains its plasticity is good, and this agree with the Al content is6%has the highest relative compression rate.In3000times of scanning electron microscope to see due to the compression caused by the local temperature rise and the formation of the molten droplet droplet, contrast to DSC figure,we find that, caused by compression of the local temperature rise up to866.6℃.