Chemical and Biological Engineering ETDs

Publication Date

6-28-1978

Abstract

A study of the fracture toughness (in this case, Gic) of steel-aluminum deformation welds using a specially developed double cantilever beam fracture toughness specimen is presented. Welds made at 350C were heat treated at 360, 380, 400, 420 and 440 C.

An intermetallic reaction product layer of Fe2Al5 is formed at the steel-aluminum interface with increasing heat treating temperature and time by a process of nucleation and growth of discrete particles. A transition in toughness from a higher average Gic value (6097 N/m) to a very low average Gic value (525 N/m) is observed. The decrease in toughness is accomplished by an increase in Fe2Al5 particle diameter from 4 to 8 um. Failure at the higher toughness values is characterized by ductile rupture through the aluminum. At the lower toughness values, failure occurs between the aluminum and the Fe2Al5 reaction product layer. A vacancy condensation void layer forming in the aluminum adjacent to the Fe2Al5 is shown to cause the embrittlement. Techniques established in this study are applicable to other dissimilar metal composite systems.

Document Type

Dissertation

Language

English

Degree Name

Chemical Engineering

Level of Degree

Doctoral

Department Name

Chemical and Biological Engineering

First Committee Member (Chair)

Stanley Elmer Logan

Second Committee Member

Marion Marvin Cottrell

Third Committee Member

Youn-Chang Hsu

Download

Share

COinS