Banca de QUALIFICAÇÃO: DAYSELANE PEREIRA DOS SANTOS

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : DAYSELANE PEREIRA DOS SANTOS
DATE: 28/04/2026
TIME: 10:00
LOCAL: Sala de reuniões do Laboratório Institucional de Microscopia e Metrologia da UFRN (LIME/UFRN)
TITLE:

Determination of the Ductile-to-Brittle Transition Temperature of Advanced High-Strength Steel Sheets by Single-Pass Pendulum Sclerometry

KEY WORDS:

Ductile-to-Brittle Transition Temperature, Advanced High-Strength Steels (AHSS), Single-Pass Pendulum Sclerometry, Scratching Energy.

PAGES: 48
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Metalurgia Física
SPECIALTY: Propriedades Físicas dos Metais e Ligas
SUMMARY:

Advanced High-Strength Steels (AHSS) are widely used in the manufacturing of structural components for automotive bodies due to their excellent strength-to-weight ratio, which results in lighter and, consequently, less polluting vehicles. These steels exhibit a microstructure characterized by a highly ductile ferritic matrix and a second high-hardness constituent—martensite, bainite, or both—dispersed within the ferritic matrix. Owing to this microstructure, cracks are commonly nucleated at cut edges during punching processes, which may lead to defects in subsequent operations involving edge stretching, ultimately resulting in component failure by fracture. Previous studies have shown a transition in the fracture mechanism of AHSS from ductile (plastic deformation by shear) at room temperature to brittle (cleavage) at subzero temperatures. Therefore, performing the punching of AHSS sheets at such temperatures may eliminate defects associated with operations carried out at room temperature. In this context, knowledge of the ductile-to-brittle transition temperature (DBTT) of the studied AHSS becomes imperative. Typically, Charpy and Izod impact tests are employed to determine the ductile-to-brittle transition curve in metallic materials. However, AHSS are often supplied as thin sheets, which prevents the preparation of specimens with the dimensions required by these standardized tests. Thus, an alternative approach is to obtain the ductile-to-brittle transition curve of these steels through single-pass pendulum sclerometry by measuring the energy consumed during the tests. Accordingly, the main objective of this work is to present a methodology and the results obtained in determining the ductile-to-brittle transition curves of the following AHSS grades: FB580, DP780, DP980, and TRIP780. For this purpose, a single-pass pendulum sclerometer, designed and built at the Manufacturing Laboratory of UFRN, was used, capable of measuring the energy consumed during scratching. The samples were tested over a temperature range from −160 °C to +120 °C, in intervals of 15 °C.

COMMITTEE MEMBERS:
Presidente - 1545410 - ANDERSON CLAYTON ALVES DE MELO
Interno - 1938946 - NICOLAU APOENA CASTRO
Interna - 1481705 - SALETE MARTINS ALVES