感谢您在中国材料大会2019提交您的论文至Materials Science Forum。
On the first place, I would like to clarify the confusion that seems to have arisen. The publication date you were informed of is related to the high publication demand in MSF journal this year. We received many titles to be published this year earlier last year which resulted in the queue. I can see the confusion by the statement from the agreement which refers not to the online publication but the date when authors get access to the complete edited issue which is provided prior to the online publication. From what I can see, the online access was provided to authors back in February.
We understand the concern about graduation. We found the possibility to move online publication to May. Hopefully, it will prevent any issues with graduation. However, in case of any issues, students are welcome to contact us at email@example.com for acceptance letters that would confirm the publication of their papers in our journal.