|
内容記述 |
No definite statement as to the age-hardening of Duralumin series alloys in their quenched and strained condition has been made yet. Some say the ageing process is accelerated in this condition, and others say it is delayed. The cause of these contradictory conclusions is considered to be the delicacy of the testing method, on account of which other factors will come to have some influence on the ageing process. Now, analysing the quenched and strained condition of the alloy, there are found two states, that is, the plastically deformed state and the elastically strained state, adjoining each other. Accordingly the study of the ageing effect in the quenched and strained condition may be divided into two; namely, the ageing after the plastic deformation and the one taken place in the elastically strain condition. There are numerous investigations on the former case, the ageing of the alloy subjected to plastic deformation following quenching, but none on the latter. The object of the present study is to make this point clear and to deduce, after all, the age-hardening of the Duralumin series in their quenched and strained condition proper. The results of the experiment indicate that when ageing this series alloys with the application, during the whole period of their ageing, of elastic stress subsequent to quenching, no appreciable change occurs in the ageing effects, but when ageing with plastic deformation applied (deformed and then aged), both proportional and elastic limits as well as proof stresses are clearly increased as compared with those of naturally aged alloys. Applying the foregoing considerations to the ageing of quenched materials in the strain condition, which is the object of the present investigation, following statement may be made: the elastic limits etc. in the plastically deformed part will have higher values than in the simply aged part, but in the adjacient part with elastic strain, the mechanical properties will be much the same as in the naturally aged part. The quenched and strained condition, however, is a combination of plastically deformed area and elastically strained one. Therefore, the aged materials, when quenched and distorted, should indicate somewhat higher elastic limit etc. than those naturally aged. |
SA4146810.pdf (476.5 kB)
