The Design Disk-model Constant Load Material Tester And Research Of Constant Load Test

This dissertation is a part of the overall researches on plasticity andsuperplasticity of CAMS. Song Yuquan. On one side, according to the basicthought posed by him, it is the effect of load that the plastic and superplasticforming almost occur in practice production.With the more development ofmodern machinery technology and precision deforming technology, givingquantitative calculational results of deformation law under load is of advantageto connect the researches on mechanical property of material with practiceproduction. Consequently, the forming law and property of material under loadwill be optimization and developed farther. On the other side, the study fruitscatena of Prof. Song demonstrates adequately that the plastic and superplasticdeformation-mechanics-law not only have relation with stress condition, butalso contact with deformation route. Among numerous deformation routes, theroute under constant strain rate, constant-velocity and constant load is one ofthree typical routes. Therefore the research on constant load test is a importantpart of the researches on plasticity and superplasticity. Whereas, the currentelectronic universal material tester have many functions, but its price is high,and its mechanical and control configuration are complicated. In addition, thereare some disadvantages when the tensile test under constant load is done usingelectronic universal material tester, such as the adverse effect of the load waveresult from the closed-loop feedback on the material whose structure is verysensitive, the insufficient of loading ability and load-holding ability.Notwithstanding the lever-model constant load material tester overcomes theshortcomings of the electronic universal material tester, it also has several flaws.Such as the horizontal directional offset of weights when it falls, the widerinterval of autocontrol loading, and the more increaser of the lever scalezooming in, the less extension of the deformation. According to all above, theaim of this dissertation has been set down, i.e. designing a kind of disk-modelconstant load material tester, which has simple construction and low price,supplies comprehensive experiment information, records exactly, operateexpediently. In particular, it fits into research the mechanical property and lawof ordinary plastic and superplastic material under constant load. In this dissertation, on the basis of Prof. Song's theory about load-transitionmeasurer that had been raised up in 1989, the design theory of disk-modelconstant load material tester is set down, i.e. regarding the net weight ofweights as source of load, through two disks which is of same torque butdifferent radius, the load will be zoomed in and brought to bear on the sample.Consequently the weight and direction of load will not be changed. Accordingto the design theory, two total structure design projects, including the part ofaccessory structure and system-control, about disk-model constant load materialtester have been constitute. In the course of tester design, the mechanicaltechnology, electronical technology and computer technology has been appliedsynthetically. The constant load tensile test is carried out under the computercontrol and the test data will be records exactly. The tester also has the abilitiesof, using the mathematics treatment software, computing the test data.Sequentially, this kind of material's total information about mechanical propertywill be received. Using the advantage of lever-model constant load materialtester for reference, this tester not only has all functions but also overcomes theshortcomings of the lever-model constant load material tester. In this dissertation, Tests under constant load were conducted respectivelyat room temperature (18℃) and superplastic temperature (Zn-5%Al is 340℃,AZ31 is 500℃) on typical superplastic alloy Zn-5%Al and magnesian alloyAZ31. Furthermore, the relax tests were also carried out at superplastictemperature. On the basis of foregone theoretics production, constant load testdata of plastic and superplastic material was processed. By generalizedmeasuring methods, and the forming law of strain rate sensitivity index m,strain hardening index n and stress relaxation index τwas acquired. The test research content of the dissertation is only a part ofmacrocosmic deformation joining microcosmic deformation mechanismin plastic and superplastic tension und constant load, and is also thetheoretical base of microcosmic deformation theory as well as...