Interpretation of X-ray Powder Diffraction Patterns . By H. Lipson and H. Steeple. Pp. viii + 335 + 3 plates. (Mac-millan: London; St Martins Press: New York, May 1970.) £4.

X-Ray Diffraction

Soft materials are materials with a low shear modulus relative to their bulk modulus and where elastic restoring forces are mainly of entropic origin. A sparse population of strong bonds connects molecules together and prevents macroscopic flow. In this review we discuss the current state of the art on how these soft materials break and detach from solid surfaces. We focus on how stresses and strains are localized near the fracture plane and how elastic energy can flow from the bulk of the material to the crack tip. Adhesion of pressure-sensitive-adhesives, fracture of gels and rubbers are specifically addressed and the key concepts are pointed out. We define the important length scales in the problem and in particular the elasto-adhesive length Γ/E where Γ is the fracture energy and E is the elastic modulus, and how the ratio between sample size and Γ/E controls the fracture mechanisms. Theoretical concepts bridging solid mechanics and polymer physics are rationalized and illustrated by micromechanical experiments and mechanisms of fracture are described in detail. Open questions and emerging concepts are discussed at the end of the review.

/pdf/fracture-and-adhesion-of-soft-materials-a-review-4ydkznlufz.pdf

Fracture and adhesion of soft materials: a review.

The Physics of Rubber Elasticity (J. Meixner)

Friction stir welding/processing of metals and alloys: A comprehensive review on microstructural evolution

Titanium alloy (Ti–6Al–4V) is one of the materials extensively used in the aerospace industry due to its excellent properties of high specific strength and corrosion resistance, but it also presents problems wherein it is an extremely difficult material to machine. The cost associated with titanium machining is also high due to lower cutting speeds (

Machinability improvement of titanium alloy (Ti–6Al–4V) via LAM and hybrid machining

Strain-induced crystallization of natural rubber was discovered in 1925 by the means of x-ray diffraction and has been widely investigated by this technique until today. The studies devoted to the structure of the crystalline phase of natural rubber are first reviewed. This structure is strongly anisotropic and can be related to the exceptionally good strength and fatigue properties of this material. The relationships between strain-induced crystallization of natural rubber and its mechanical response, during static or tension-retraction tests, are also reviewed and discussed; in particular, the hysteresis of the stress-strain curve is mainly explained by strain-induced crystallization. The kinetics of crystallization under both static and cyclic deformation is also discussed, as well as the influence of different factors, depending either on material composition (crosslink density, carbon black fillers) or on external parameters (temperature, strain rate…).

/pdf/strain-induced-crystallization-of-natural-rubber-a-review-of-1ilgu4ftrw.pdf

Strain-induced crystallization of natural rubber: a review of x-ray diffraction investigations

The present paper deals with the fatigue crack growth in a carbon black filled cis-1,4-polyisoprene rubber under relaxing loading conditions. The study focuses on the determination of the scenario of crack growth. For this purpose, an original “microcutting” method is employed to observe microscopic phenomena involved in the growth of the crack with a SEM. It reveals that the cavitation induced by the decohesion between zinc oxides and rubber matrix is the major fatigue damage and that the crack tip is composed of stretched elliptical areas surrounded by highly stretched and crystallized ligaments. Finally, the observations are considered to establish the fatigue crack growth mechanism.

https://hal.archives-ouvertes.fr/hal-01010941/document

Mechanism of Fatigue Crack Growth in Carbon Black Filled Natural Rubber

https://hal.archives-ouvertes.fr/hal-01005980/document

Comparison of TIG welded and friction stir welded Al–4.5Mg–0.26Sc alloy

Commercially pure copper was joined to a 1050 aluminum alloy by friction stir welding. A specific configuration where the tool pin was fully located in the aluminum plate was chosen. In such a situation, there is no mechanical mixing between the two materials, but frictional heating gives rise to a significant thermally activated interdiffusion at the copper/aluminum interface. This gives rise to the formation of defect-free joints where the bonding is achieved by a very thin intermetallic layer at the Cu/Al interface. Nanoscaled grains within this bonding layer were characterized using transmission electron microscopy (TEM). Two phases were identified, namely, Al2Cu and Al4Cu9 phases. The nucleation and growth of these two phases are discussed and compared to the standard reactive interdiffusion reactions between Cu and Al.

/pdf/interfacial-reaction-during-friction-stir-welding-of-al-and-57gp17xyiz.pdf

Interfacial Reaction during Friction Stir Welding of Al and Cu

https://hal.archives-ouvertes.fr/hal-01007377/document

Bertrand Huneau

Papers

Strain-induced crystallization of natural rubber: a review of x-ray diffraction investigations

Mechanism of Fatigue Crack Growth in Carbon Black Filled Natural Rubber

Comparison of TIG welded and friction stir welded Al–4.5Mg–0.26Sc alloy

Interfacial Reaction during Friction Stir Welding of Al and Cu

The ternary system Al-Ni-Ti Part I: Isothermal section at 900°C; Experimental investigation and thermodynamic calculation